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?"
Re:Just get... (Score:2, 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:Why not quad core? (Score:5, Insightful)
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: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:3, Insightful)
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 more attractive than sinking gobs of money and time into trying to design something new that may or may not pan out to be all that attractive.
steve
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 are diminishing returns for more than 2 CPUs, except for parallel applications, and there aren't that many of those.
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: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:Does dual core mean dual licensing costs? (Score:5, Insightful)
steve
Integrated memory controller (Score:5, Insightful)
Re:939 is now (Score:2, Insightful)
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: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.
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: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 shuts down cores not in use.
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 1MB of L2 cache (and of course it's own 128K of L1 cache as well). Combine that with the huge amount of I/O bandwidth they've got with Hypertransport and really the chip is well designed to accept a second core.