AMD Going Dual-Core In 2005 309
gr8_phk writes "We recently learned of Intel's
plans to go dual-core in late 2005. Well it seems AMD has
decided to follow suit. It should be noted that the K8 architecture has had this designed in
from the start. Will this be socket 939 or should I try to hold out another year to buy?"
Why not quad core? (Score:4, Funny)
Re:Why not quad core? (Score:5, Funny)
Re:Why not quad core? (Score:5, Insightful)
Re:Why not quad core? (Score:3, Interesting)
Re:Why not quad core? (Score:3, Funny)
You mean 8 [and not 4?]. This is a computer, you're legally bound to use a power of 2.
And this got a 5 insightful, how?
Re:Why not quad core? (Score:5, Interesting)
Re:Why not quad core? (Score:5, Informative)
AMD's dual-core server processors will share a single memory controller, Weber said. This won't create a bottleneck because a server with two Opteron chips, and therefore two memory controllers, already has more than enough memory bandwidth required to run that system, he said.
"It's always a juggling act to add a little more processing and a little more memory. Right now, we have plenty of memory and I/O bandwidth, so we're adding processing," Weber said.
The dual-core chips will work with current socket technology in motherboards that are rated for the specifications of the dual-core chips, Weber said. A BIOS change will be required, but otherwise the chips will work in the same sockets as single-core Opterons, he said.
Re:Why not quad core? (Score:2)
Wow, that's a helluva significant statement to make. More bandwidth and cache never hurts... you just get diminishing returns. Either it's marketspeak-- "You need two cores, pay up!" --or it flies in the face of some pretty basic assumptions I have about processor and cache architectures. Perhaps he meant, "Our cache and bandwidth is currently large enough to support two processes without being detrimental, given two pro
Re:Why not quad core? (Score:2)
Re:Why not quad core? (Score:2)
Integrated memory controller (Score:5, Insightful)
Re:Integrated memory controller (Score:3, Interesting)
Re:Why not quad core? (Score:3, Insightful)
Ohh, and as for cache, that fortunately isn't a problem at all as each core comes with it's own 1M
Exactly my first reaction! (Score:5, Insightful)
Maybe those processors do have enough memory bandwidth to load two of them completely doing SAXPY? Assuming 12 GFLOPS sustained (3 GHz, 2 cores, separate ADD and MUL on each) you need to feed input vectors at 12*8 bytes/double = 96 GB/sec, for, say 1 GHz memory bus it is translated into 96*8=768 memory pins only for input -- well, wider than I've seen on desktop PCs...
When you start doing anything else , the roundtrip time between processors and memory (latency) becomes more important than raw bandwidth.
Paul B.
Re:Exactly my first reaction! (Score:5, Informative)
Bringing processors and (large) memories closer to each other does not help much, as, as you mentioned, there is an order of magnitude difference between processor clock speed and memory access speed. The physical reason for this is that to do a certain operation on one pipeline stage in a processor you need to charge a clock line passing through a couple dozen to couple hundred gates; in memory case you have to charge the word line passing through sqrt(1G)=30,000 gates. It takes time (RC, unless one uses superconductors and forgets about R
The only rerasonable solution is, indeed, to make memory blocks smaller and closer to processor elements, making them essentially registers/caches, not RAM.
Oh, and, BTW, in the rather naive picture on the link you sent, the solution will not work that well if you have multiple processors -- you have to make sure that each can talk to other's memories (in SMP case) AND to each other.
Paul B.
Re:Exactly my first reaction! (Score:3, Interesting)
Re:Why not quad core? (Score:5, Informative)
The dual core cpu might have the pins for two seperate memory bank arrays or just the pins for one. Either way, the situation as far as dual k8s go is not really different from what we have already. Either way, it's a few steps above the p4 design: shared cpu bus to northbridge to memory. (yech! with a single proc, this introduces latency, with multiproc, you get contention and latency at every level)
AMD's cpu interconnect is so well thought out... it gives me the warm fuzzies pondering it:
A uniproc hammer needs one h-link for io.
A dually needs two per core: 1 for core to core, 1 for io (though all the io on all the boards I have seen feeds to only one proc's h-link... so that you don't lose PCI busses and such if you have only one proc installed, I suppose).
Quad and above requires three: each core links to two other cores, leaving one h-link per core for io. One could have a pci-e bus per proc, if one desired. But again, I haven't seen a design that doesn't feed all io into a single h-link.
Since no one uses the extra h-link anyway, a dual core package for a dual core system would need only one external h-link (saving some cash).
A quad core, dual package system would require three h-links feeding out of each package, though. But even then, the number of h-links laid out on the mobo is reduced and the whole shebang should be cheaper.
Intel's "one huge shared bus" + northbridge design is definitely being trampled...
Re:Why not quad core? (Score:5, Informative)
Ah but with multi-core chips they can transduce their flux capacitors with the onboard trans-mogrification controllers. Seriously "reduced bus conflicts with their memory space", what does that mean?? That's gibberish.
P4, presumably, like the P6 GTL+ host bus is a shared bus (like most buses are). Only CPU can use the bus at any one time. If the bus does x GB/s, that's only to one CPU at any given time - effectively it is shared. Further, P6 and P4 do not have integrated memory controllers, and must access RAM via the (shared) GTL+ bus, if it is not in cache. Eg, a 4 CPU machine looks like:
Also GTL+ is limited to 4 CPUs and one controller. To get 8 CPUs some controller vendors have invented a GTL+ 'bridge' to stitch 2 GTL+ buses together, but that just makes things worse really from a scaleability POV I'd imagine.
The K8 on the other hand uses a point-to-point (PtP) serialish, packet based transport, HyperTransport [hypertransport.org] to interconnect CPUs and has onboard memory controller(s) (connected internally via HyperTransport links). A 4 CPU K8 machine looks like:
Each of the lines out of a K is a HyperTransport link. Each MC is integrated into the die itself. (you'll have to imagine interconnects and right-hand top/bottom MC's lining up with the K symbols, cause /.'s filter is chomping whitespace in some strange way on me).
Each CPU has 4 HT links, two to other CPUs, two to its (integrated on die) memory controller. For dual CPU setups, each CPU needs only link to another CPU obviously. Indeed the difference between 2xx, 4xx and 8xx AMD Opteron CPUs is the number of HyperTransport links. Indeed in large multi-CPU (ie 8+) SMP setups one need not attach a memory controller to each CPU, one might choose to have a central "cross-bar" of fully-meshed K8s who then connect to peripheral K8s which have memory controllers and hence RAM. Tis all down to the board designers I guess. And a bit of a fun computer science problem too in terms of designing optimal 'networks' of interconnected nodes with the best compromise of maximum node to node distance for lowest number of required interconnects.
The K8 is actually a ccNUMA (cache coherent, Non-Uniform Memory Architecture) machine, in SMP configurations. Ie, different memory is at different distances to different CPUs, or to put it another way, some memory is local, other memory is distant, some memory may be more distant than other memory. Eg, for the top-left CPU to access RAM on it's "local" MC is obviously potentially far quicker, in terms of latency, than to access "distant" RAM on another node, and to access memory on an adjacent K8's memory controller will have lower latency than to access memory allocated in the bottom-right CPUs RAM. A good OS aware of the issues can try ensure to keep processes on the CPUs to which that processes memory is "local" and hence maximise performance, but it's quite a juggling act (Linux has some NUMA support).
What AMD will do for multi-core we dont know. For certain the individual cores will be connected by HyperTransport. Most likely AMD will give each core their own dedicated memory controller, which would simply make a multi-core SMP be exact same in terms of architecture as the current dual K8 architecture (ie 2xx opteron), and hence no different in terms of bandwidth contention than for existing SMP Opterons.
It will make large SMP machines a lot easier to build though. Eg
Re:Why not quad core? (Score:3, Informative)
Re:Why not quad core? (Score:5, Informative)
Yes..the evil of all machines
the reason why when the AC is not on in my house, and it is 90degrees outside, my computer resets
and of course..the reason why we're not going quad core
well..at least that's my personal opinion...as for the real reason...probally for profit...
Re:Why not quad core? (Score:5, Funny)
The number of processor cores doubles every eighteen months.
Re:Why not quad core? (Score:2, Funny)
Re:Why not quad core? (Score:3, Insightful)
Windows professional comes with a license for 1-2 CPUs. Above that you need to purchase one of the server edition, and it starts becoming *very* expensive.
Soon 2 CPUs will be for the masses, they already are with hyperthreading in a way. However 4 and above really are for servers; multi-user environments, etc.
Also while it is easy to exploit 2 CPUs in a desktop environment (roughly speaking 1 for the O/S, the other for the applications) there
Re:Why not quad core? (Score:3, Insightful)
The threading was planned from day one to support multiple processors with out any special coding. It's been a few years, but I think i'm right.
If Microsoft is smart, they'll implement something like this for Longhorn and whatever binary executables are used.
Re:Why not quad core? (Score:3, Informative)
Because the overall size of the die is a tremendous factor in the cost of a processer. Because of that, die sizes tend to stay relatively constant over the years.
As manufacturers are able to squeeze the transistors in more tightly, then you see more circuitry appearing. As they move to 90-nanometer production, they're going to be able to pack on more transistors, and using dual cores becomes an economic possibility. However, throwing FOUR cores on would make the die large enough to be an economic di
A lot more info over at anandtech... (Score:5, Informative)
In answer to poster's socket question: (Score:5, Informative)
Re:In answer to poster's socket question: (Score:4, Informative)
They already have dual channel memory cntrl (Score:3, Interesting)
for additional AMD dual core story links (Score:5, Informative)
Demise of processors predicted! (Score:5, Funny)
actually it'll probably be more like the processors gets so big that you just clip things onto the outside of it and it takes the place of the motherboard.
Re:Demise of processors predicted! (Score:5, Funny)
Re:Demise of processors predicted! (Score:2, Funny)
As the number of pins continues to increase the mass does also, at some point processors will achieve such a large mass they will collapse in upon themselves.
Nope. that's where the heat comes in. As they get larger they'll also get hotter. The heat will cause an internal pressure that will counterballance its own gravetational attraction.
Eventually fusion will occur and the power supply can be moved on chip also.
Re:Demise of processors predicted! (Score:3, Informative)
Re:Demise of processors predicted! (Score:3, Insightful)
read.
He means that some point down the road, the CPUs will be bigger than the boards themselves, thus the joke.
Does dual core mean dual licensing costs? (Score:5, Interesting)
How long will it take to argue that consumers with a dual core processor should pay 2x the price? I'm betting not long.
yes (Score:3, Funny)
The commercial software vendors may be slovenly
about keeping up with security patches, but they
jump on extra money like rabid ferrets on raw meat.
Re:Does dual core mean dual licensing costs? (Score:5, Insightful)
steve
What AMD is really doing (Score:5, Funny)
939 is now (Score:2)
http://www.theregister.co.uk/2004/06/01/amd_939/
Re:939 is now (Score:2)
Isn't that fairly obvious though? I've always factored in the cost of a new motherboard and new memory to go along with any new CPU purchase because I know the crap I'll have will be obsolete in a year or two when I go to upgrade the CPU. I have NEVER upgraded to a faster CPU by swapping it out and keeping the same motherboard because then I feel cheated as I'm left with a CPU with no home. I t
Re:939 is now (Score:2)
In a year, there'll be something bigger and faster (and probably incompatable) out anyways. It's always like that, if you haven't been paying attention.
Even if you bought a motherboard today, in a year the top of the line processor probably won't work on it anyways.
A year? (Score:5, Funny)
You're planning on waiting more than a full year between computer upgrades? Are you sure you're on the right website?
shall I invest in heatsink business? (Score:5, Interesting)
You'll need a new motherboard. (Score:4, Informative)
You'll need a new motherboard.
The DDR memory interface appears to wrap around both L2 caches, meaning that it looks like both cores have their own 128-bit memory interface; whether or not both memory controllers will be enabled is another thing, but if this is true we have a number of implications to talk about. If dual core Opterons do indeed have two memory controllers, the pincount of dual core Opterons will go up significantly - it will also make them incompatible with current sockets. AMD is all about maintaining socket compatibility so it is quite possible that they could only leave half of the memory controllers enabled, in order to offer Socket-940 dual core Opterons. AMD isn't being very specific in terms of implementation details, but these are just some of the options.
Re:You'll need a new motherboard. (Score:2)
This is NOT two ENTIRE Opteron processors plunked on the same die.
AMD have designed the ability to connect to TWO cores into the SysReq part of the processor since the beginning.
The SysReq connects on the other side to a crossbar that connects in turn to the HyperTransport Controller and the Memory Controller.
A dual core processor will still only have a 128-bit memory controller.
AMD have stated that the processors will be socket compatible. This also suggests that S939
Re:You'll need a new motherboard. (Score:5, Insightful)
I understand your reasoning, but according to this article [infoworld.com] (I found the link on Ace's Hardware [aceshardware.com]) the dual core chips will be compatible with current motherboards and sockets with as little as a BIOS flash (to recognise the new CPUID I assume). The downside of this is that the two cores will SHARE the dual channel memory bus. But because the bus is so effiencent, each core will probably STILL get more bandwidth than most P4s. At worst it shouldn't be much worse than having two single channel Athlon64s (which also are often faster than the P4). I think this is FANTASTIC news. For one thing, this means you could put FOUR CORES in that dual opteron SFF PC that was revealed a short while ago.
Really, it only makes sense. A dual channel processor has 939 pins, a single channel has 754 pins. So while some are power, you're looking at about 190 pins for the second memory channel. So that would mean that to have two cores on one die with their own memory channels, you'd need 1120 pins or so. That's a LOT of pins.
Instead of that enginering nightmare (you'd probably need 7 layer mobos to support that), we get drop in replacements that meet the same thermal requirements. Just think. You're dual operton not cutting the mustard any more? Buy two processors, drop 'em in, flash the BIOS, and now you've got FOUR processors without a new mobo or anything. All you'd have to worry about then is software licenses (unless of course you don't use any software that requirs that, for example you're all open source).
So to answer the grandparent's question, I'd say buy now. That said, I'm not sure if socket 939 will get dual cores or if it's only for 940s. I assume 939 will get them too.
Speculation: I'd like to know if the dual channel memory controler is shared by the two cores (like some kind of cross-bar architecture thing like nVidia used to promote) or if each core got exclusive access to one of the two channels. My guess is the former.
More speculation: Will there be a socket 754 dual core? That'd be cool, and I don't think the performance would be too much of a problem memory wise, unless you were doing memory intensive tasks. For CPU bound tasks I think you'd be fine.
Re:You'll need a new motherboard. (Score:3, Informative)
AMD's dual-core server processors will share a single memory controller, Weber said. This won't create a bottleneck because a server with two Opteron chips, and therefore two memory controllers, already has more than enough memory bandwidth required to run that system, he said.
"It's always a juggling act to add a little more processing and a little more memory. Right now, we have plenty of memory and I/O bandw
What we really need... (Score:4, Funny)
should I try to hold out another year to buy? (Score:4, Interesting)
From my own personal point of view, my dual athlon 1.5ghz is still holding out beautifully. When the cash comes my way Im banking on a powerbook. Truth is I dont need another desktop just yet. However if i had a stupid disposable income, and one that predictably would hold out till these dual cores come out id proabably get one now, and get one later.
When I built this machine I bought the highest spec parts I could afford at the time and I havent upgraded for 2 or 3 years aside from upgrading the graphics card. The rule I live by is get the best available that you can afford at the time and it should keep you going for a good while.
Im running gentoo box; faster processors would be very nice for source compiles but I gave up on churning out seti blocks a while ago and dont have a massive reason for further processor power
Re:should I try to hold out another year to buy? (Score:2)
Which is perhaps the most expensive way to get what you need.
I take a look at pricewatch [pricewatch.com] under "hard drives", here's the matrix:
Notice that the price starts at a high of 77 cents per GB, then falls almost 40% in price per unit down to
Re:should I try to hold out another year to buy? (Score:3, Funny)
Signifigant other...you mean my laptop?
Really nice alternative to dual processor systems (Score:5, Interesting)
Some years ago I was thinking about getting a dual processor system. Alone the motherboard was two times as expensive as a similar single processor one, applications did not support it all and so on. I hope newer applications are ready for dual cores. Quake III was the first game I know that used two processors and finally I can consider that animated desktop background.
Is there a list which applications can effectively use dual cores besides obvious things like webservers?
Re:Really nice alternative to dual processor syste (Score:5, Informative)
Re:Really nice alternative to dual processor syste (Score:2, Interesting)
Re:Really nice alternative to dual processor syste (Score:4, Insightful)
Multithreaded and multi-process.
If Firefox is rendering a page, you've got Firefox doing the rendering, the GUI working with video drivers, disk drivers looking at/updating your browser's cache, kernel code managing disk cache, kernel code managing network activity, and perhaps even firewall code running.
Whether you use Linux or Windows, there are a LOT of things running that you don't see in normal process list.
Now, will dual CPU's speed up that render time in Firefox? Not to any significant amount. But having used a LOT of dual-CPU systems, I can say that under heavy load, the machine will be much more responsive. If that helps your workload, it might be worth it. If it doesn't, it's not worth it.
As an example, at work I have a dual AthlonMP 1800+. At home, I have a single AthlonXP 3200+. For what I do at work, the single-proc chip would suck rocks. For what I do at home, the 1800+ would not compare to the 3200+. It's all about your usage.
steve
Re:Really nice alternative to dual processor syste (Score:2)
You'd notice the most difference if you had one CPU bound app and a ton of others that weren't. For example you were running some big simulation or POVray, and at the same time checking your e-mail and surfing the web. With two processors even if the prorams don't use them (they aren't SMP aware), as long as
Re:Really nice alternative to dual processor syste (Score:2)
Will it at least inlcude a cupon to buy a Cray?
He he he.
Socket 939!? (Score:2)
Re:Socket 939!? (Score:2)
They are identicle in features (dual channel) except the 939 lacks one pin. That pin just happens (wink) to be a HyperTransport link that was removed. This means there are not enough links to support multi-processor setups because you can't have the links to the other processors because you don't have enough. This is basically a marketing move to segment the workstation market from the desktop market. There is no (techincial) reason they couldn't have used socket 940
This really sucks. (Score:4, Funny)
Yeah, right
Damnit, they had to come out with this (Score:5, Funny)
Hey, Wal-Mart brand noodles are only 8 cents!
Longhorn (Score:5, Funny)
Its amusing to watch the chip manufacturers scramble desperately to meet the recommend specifications for Longhorn in time.
Oh, c'mon don't look at me like that. A slashdot story without some kind of Microsoft snipe just wouldn't be the same now, would it?
Alright, fine. I'll pick on SCO or AdTi next time. Sheesh. /me crawls back under his rock
Re:Longhorn (Score:2)
why go for CMP and skip SMT (Score:5, Interesting)
While CMP processors can give us rougly the same performance of a standard SMP system (somewhat faster due to interprocessor communication and shared memory, but also slower due to a larger memory bottleneck) I don't think that a CMP system would compete with a simultaneous multi-threading (SMT) solution.
While Intel's response to SMT (hyperthreading) has some benifits the performance of it is rather lackluster. The reason has more to do with their particular implementation. If you've read about the initial observations on SMT an 8-way SMT processor was shown to outperform a 4-way CMP processor. Now, I must note that the 8-way smt processor had more functional units then the cores in the 4-way CMP processor, but the overall area of the 8-way SMT processor would be much much smaller (far less structures need to be duplicated for SMT as opposed to CMP). For more information on this check out some of the papers at http://www.cs.washington.edu/research/smt/
What I don't understand is the insistance of the industry to use CMP first. From everything I've read, an 8-way SMT processor should take up less die space then a two way CMP processor. Even assuming that the 8 way processor contains more functional units. It kind of makes sense that a CMP processor is faster when there aren't enough threads to fully utilize a SMT processor (say only 2 or 3 threads that want full cpu usage). I guess SMT is a big chance in the model of programming and application development (I'm currently running research on the subject which is why I'm so interested in it). Is the reason to embrace CMPs simply because there's less new technology to add (they "just" have to interconnect two cores as opposed to adding the extra logic for SMT).
Does anyone else have any other opinions regarding this matter, or any idea why no one seems to be fully embracing SMT's potential.
Philip Garcia
Re:why go for CMP and skip SMT (Score:5, Informative)
Intel stuck SMT into the Pentium in order to balance out the some of the negative effects the go hand-in-hand with a processor that has a LONG pipeline. AMD has a much shorter pipeline (especially when compared to the new Prescott) and therefore they don't suffer much of a penalty when a mis-predict happens. Also, if I remember correctly the Athlon was already known being extremely efficient in terms of resource allocation within the processor since AMD can't afford to just dump tons of extra cache onto the chip.
Both of these things taken together means that using up extra real estate on the die of the Athlon in order to get SMT isn't really worth it in terms of the performance it would bring. Even on the Pentium the benefits aren't all that hot and it's only in specific types of code that you see any impresive speed gains.
Re:why go for CMP and skip SMT (Score:3, Insightful)
You really can't figure out why they're focusing on CMP? It's not exactly tough. They don't have to design a new architecture. That saves a LOT of money in R&D, and (more importantly) cuts a LOT of time off of time-to-market. It's also VERY easy - especially with the Opterons. Copy the lithograph, connect the HT links, and you're done. To top it all off, it's something that will fetch a good price premium
To summarize, it's easy, fast, and will (supposedly) make them more money. That's a lot
And with all of that processing power.... (Score:3, Funny)
Dual core... (Score:2)
Why not 8 x i486 cores? (Score:4, Interesting)
Re:Why not 8 x i486 cores? (Score:3, Insightful)
Did you miss the part about shrinking it down to modern geomerty, meaning it would run faster on less power (read less heat) than the original? Sure a 90nm i486 isn't going to run at 3.6GHz like a P4, however I expect it would run a good amount faster than a 486DX2-66 once did.
Also, having 30 or so of your 486 cores sitting idle most of the time would result in alot of wasted electricity.
Modern power control circuitry sh
Re:Why not 8 x i486 cores? (Score:5, Informative)
Unfortunately, nothing will beat the architectural gains which have advanced since the 486 era, and the "worst case" pipeline waits will keep your clockspeed at an insanely low level.
Let me try to explain. The 486 had a 5 stage pipeline - fetch, decode, dispatch, execute, and writeback. Now, each of those pipeline stages isn't going to take the same "minimum" amount of time - some of them are fixed by things other than switching latencies. So, say your execute stage is fine taking only 1 clock cycle up to, say, 2 GHz (a minimum latency of 500 ps), but your decode stage, simply from physical concerns, is going to take at least 5 ns to complete. This means that the maximum you can ramp the clock speed up to is 200 MHz, because each stage in the pipeline has to take 1 clock cycle, so if 5 ns is your minimum, you'll have a max clock speed of 200 MHz.
The solution, though, is obvious - break that "5 ns" decode step into multiple pipeline steps - say, 5 of them, each taking 1 ns each. Now your maximum clock frequency is 1 GHz. The problem is that your pipeline is now 9 stages long, and you have a new architecture - which is precisely what Intel did several times over to allow the clock speed to ramp.
And that's just the pipelining limitation. There are other architectural problems with "ancient cores" as well. One basic problem is that the x87 floating-point architecture is crap. It's stack-based, which means you can only do math with the "stack head". So in order to store things in the registers, you need to use the FXCH instruction to switch the stack head and one of the registers. Well, modern CPUs (the P3 and the Athlon) got around this by saying "we'll make FXCH be a zero-cycle execute when paired with an arithmetic instruction (and after the Pentium, screw it, they're free totally)". Since the modern CPUs can decode more than one instruction per cycle (3 for an Athlon), and the FXCH instruction only lives up to the decode stage, you're really not hurt, as the FXCH fills a pipeline stage that probably would've been left empty anyway. Now consider the P4, which was designed to try to encourage people to move away from x87: it does not have a zero-cycle FXCH, and its x87 performance is abysmal. (The 486 does not have a pipelined FPU, nor a free FXCH instruction. It would be even worse.)
And I haven't even mentioned register renaming yet, which works around the register limitations of the x86 ISA by creating registers that the software doesn't know about, but which the hardware can "cheat" and recognize certain compiler patterns which work around the register limitation.
In short - many core 486 CPUs would suck. Even many core Pentiums would suck. Architecturally, they're old, dead ends. The best designs for multicore processors would be the P6 design (PPro/PII/PIII/PM) and the Athlon design (K7/K8 - while the K8 is "new", it's about as new as the PM is to the P6 design). Curiously enough, Intel is likely to go with a multicore PM, and AMD is likely to go with a multicore K8.
It should also be noted that a 486DX had a transistor count of 1.2M transistors. A P3 had a transistor count of 9.5M transistors. That's an increase of about 8X - however, the P3 also has twice the data width (64-bit rather than 32-bit), 4X the L1 cache (32KB rather than 8KB), and had two instruction set enhancements tacked onto it, as well as massive architectural improvements, including, essentially, multiple versions of the 486 execute engines inside it. An 8X increase in size for those enhancements is not crazy at all.
SMP and Windows stability? (Score:3, Interesting)
While I find that multiprocs settings under Linux improve things to a significant degree (although there are still outstanding issuess with NVidia proprietary drivers and SMP), I found the opposite true for Windows.
The last time I tried, which was about 2-3 years ago, many drivers didn't seem to expect true concurency under Win2k and I was experiencing significantly more crashes on my dual P-III than when I forced the system to only use one of the CPUs. Yet it probably wasn't the hardware because that same machine was very stable with Linux.
With the advence of hyper-threading, have things improved markedly with WinXP?
Advantages of multi-core (Score:3, Insightful)
I see lots of conversation comparing this generation of processor to space heaters, wisecracks about Longhorn minimum systems (that actual article was about the predicted "average [slashdot.org]", not minimum). Not much about actual multi-cores. They're an interesting direction to go.
The current direction of single core CPUs is basically running into the most they can do with XUs, MPUs, caches, etc. Sure, you can decrease the pipeline depth below the 18FO4 that the PentiumIV supposedly has, and that can help you with serial data paths, and that makes simple XUs, MPUs, etc. faster, but the branch mispredict is still horrendous -- perhaps too high for a general purpose processor found in our PCs. The more complicated logic is possible to do, but there's only so much you can do with the data and sub-Angstrom logic.
Beyond the geek factor, multiple cores on a single die attack the same problems as putting SMP did in the first place (plus a few race conditions that otherwise may have been very rare), allowing much less manpower to design a processor that is still much faster in the end. A single threaded application will seem slower, and that will place more burden on the developers to see the light of multiple threads. Instead of allowing an XU to munge through and deal with a single thread at a time, which may be a misuse of incredible resource (like a thread that said "go to grocery store" and the XU was a race car), multiple die have correspondingly multiple XUs each with their own resources, so hard tasks can be spread across multiple cores, or simple ones can get executed in parallel with others (like a thread can take a Kia to the grocery store while another Kia goes to the Post Office). Of course, problems that cannot be divided into multiple threads do not see the advantage of multiple cores, but other tasks remain responsive without requiring a monster task to context switch.
I've read about multiple cores that share a single L2 outperforming multiple cores with dedicated L2s in specific tasks, basically one core essentially acts like a pre-fetch core under a workload and the second core can reap the benefits.
Re:Just get... (Score:2, Insightful)
You response was half right and half assed (Score:5, Informative)
While I understand the desire to build your own and preferring not to be vendor locked, you G5 fan comments are quite ignorant. The Apple G5's are well designed and exceptionally well layed out to create thermal zones serviced by different variable speed vans. It is a very quiet solution. Do not confuse the G5 with some of the homebuilt Athlon abominations that have poor layout, poor airflow, and require multiple screaming fans. YMMV.
Re:You response was half right and half assed (Score:2, Interesting)
Cpu temps in the mid 50's C. Not what I would call screaming...
Re:You response was half right and half assed (Score:3, Informative)
Re:Just get... (Score:3, Informative)
Re:Just get... (Score:5, Interesting)
Re:Just get... (Score:2, Interesting)
Re:Just get... (Score:5, Insightful)
I got to drive one of the nice newer Mercedes coupes,with a big V8 in it. They were bragging up the horsepower, so I was wanted proof. "Let me drive." I ran it hard. The owner, in the passenger seat, was impressed with the power I was pulling from it. Then asked the owner how much the car cost. Something around $100k. I handed him the keys to my car (2000 TransAm WS/6) and said "now drive this."
I paid about $25k for my car. New it was something like $30k. My car has better handling, better acceleration, better braking, and is faster. This was before I did any mods to it. The interior trim may not be as nice, but my car does have all the options including leather seats, and it turns more heads when I drive past, than a Mercedes does. It's comfortable enough for two people to ride in it all day (done that many times), and the back seats are just about as big.
Apple's are very pretty. I've used a few. I was happy that my girlfriend was on one using OS/X, but when that machine started acting flaky, we didn't buy a new Apple, we spent $1500 on really good parts. AMD 2800+, 1Gb RAM, 200Gb hdd, DVD reader, DVD writer, asus motherboard, high end video card, etc, etc.. What Apple does $1500 buy you? When we want faster, all we have to do is buy some faster components. When the G6, G7, or whatever comes out, well, you're buying a new Apple.
You can buy a new Mercedes at the really fancy store, or you can (could) buy a TransAm at any dealership. If I want more power, I grab Jegs [jegs.com] or Summit [summitracing.com], and start shopping.
You can buy an Apple at the fancy Apple store, or buy parts from a wholesaler whos "Will Call" area is the back door of the warehouse.
I still say "Pretty" every time I look at a Apple. I give them that. Then I hop back on my x86 based Linux machine and drive faster.
Re:Just get... (Score:4, Informative)
Second -- actually, we don't know that we'll be able to swap out single core Opterons with dual core Opterons. They're not out yet. The G5 is. If later on it proves to be true, then you can say that you can swap them out.
Third -- the G5 gives you access to one of the better Operating Systems around, MacOS X. That has to give it a few advantage points.
BTW -- I happen to have both a Dell Dimension 8600 and a dual 1.8ghz G5 in my office at work. When the Dell is running, you notice it. It's quieter than the thrown together PC that's also in the office, but still loud enough to notice. On the other hand, the G5 is completely quiet. I never hear the fans in there at all. I can actually see one of the fans moving from the front, but it's moving at such a slow speed that you can't hear it at all. For some of us, that is a feature.
Re:Just get... (Score:3, Insightful)
Re:Just get... (Score:2, Insightful)
So what's the point of having a fast CPU? Video encoding? Photoshop?
Answered our own question, we have.
Re:Just get... (Score:4, Informative)
Re:Just get... (Score:2, Informative)
Re:Just get... (Score:4, Informative)
Diablo II, Starcraft, Warcraft [blizzard.com]
Unreal Tournament 2004, Neverwinter Night, Dungeon Siege, Civ III [macsoftgames.com]
Myst, Riven, Exile [ubi.com]
Medal of Honor and expansions, Battlefield 1942, Ghost Recon [aspyr.com]
Ghost Master [feral.co.uk]
Quake III, Beyond Castle Wolfenstein
Escape Velocity Series, among others [ambrosiasw.com]
There are plenty of other games for the Mac platform as well, check the Apple website [apple.com] for a larger list.
Re:Just get... (Score:2)
Re:Just get... (Score:2, Funny)
Re:Just get... (Score:3, Informative)
Re:Just get... (Score:4, Funny)
We've had an internal joke in the office for years, that our in-house distribution should be named "Pornix". We think if it sold at $40, and included a one month membership to a couple of our adult sites, we'd make a fortune.
Re:End of moores law? (Score:5, Informative)
from a google search.
Moore's Law
Re:End of moores law? (Score:3, Informative)
Is this the end of moores law, at least in the form of CPU speeds doubling every 18 months? There are essentially two CPUs, I doubt each of them will get 2x faster the next 1.5 years :)
There have been quite a few posts pointing out that Moore's law actually refers to exponential growth in transistor density rather than speed.
The posters are technically correct, but the term Moore's law has come to encompass any processor-related metric that changes at an exponential pace, including processor performan
Re:What about Apple? (Score:5, Interesting)
In all probability the PPC little brother of Power5 (rumored to be called the 975) will debut at 90 nanometers and the next chip will be a ~60 nanometer dual core version possibliy called the 976.
Which if these will be called the G6 is left up to the reader as an exercise. My money is on the 976. Either way the PPC has some serious legs.
=tkk
Re:What about Apple? (Score:2)
Except it's legs are too expensive and too slow. Sorry folks, but x86 won the war. The ONLY reason I bought a Mac was to play with MacOS X. If it was ported to x86 tomorrow I would switch in an instant. PPC sucks donkey balls when it comes to speed. My 800MHz G3 iBook is horribly slow compared to my PIII-600 Intel laptop.
Well (Score:4, Interesting)
I highly doubt Apple will switch to x86, it's a pride thing if nothing else. Also, at this point, a switch would upset everything. It could have been done, potentially, with the OS-X switch. Since software was having to be ported to a new OS, a new architecture port is just one more thing. Now, however, x86 Macs would be binary incompatible with PPC Macs. That means emulation, which isn't very efficient.
I think Apple is pretty much stuck on PPC for good.
Re:What about Apple? (Score:2, Interesting)
Apples are the only RISC-based consumer desktop platform, it would be tragic if they moved towards Intel with all its legacy baggage.
Re:AMD K9 barks up the wrong branch (prediction)? (Score:4, Funny)
Re:The main issue will be memory! (Score:5, Interesting)
Yes, it does.
If you're at all familiar with the Opteron architecture, you'd realize that each chip's memory controller does, indeed go to a new memory bank.
As an example, I just bought a 4-way Opteron. It's got four seperate banks of memory on it. Each processer has a 128-bit, DDR400 memory controller, all independent of each other.
If you have a program on each CPU, accessing memory tied to that CPU, the 4-way machine I mentioned would have a theoretical memory throughput of 25.6 gigabytes/second. The theoretical throughput of a dual-Xeon machine is 5.4 gigabytes/second. That's a huge difference.
You're right, it takes some intelligent work to schedule programs on CPUs that are close to the memory the program will access. If you hadn't been in a hole for the past year or two, you'd know that there has been a lot of work put into Linux to make it handle these NUMA architectures more intelligently. IBM has some VERY large NUMA systems, and has been pouring a lot of development into Linux.
As for system costs going up so much that it would be prohibitive for a desktop, think again. AMD's entire desktop line is transistioning to the Opteron architecture. Even the lowly 1xx single-proc Opterons and Athlon64's have nearly all of the features of the highest 8xx 8-way chips. The difference between a 848 and a 148 is just reduced cache, and fewer Hypertransport lines out of the chip.
steve