Inside AMD's Phenom Architecture

An anonymous reader writes "InformationWeek has uncovered some documentation which provides some details amid today's hype for AMD's announcement of its upcoming Phenom quad-core (previously code-named Agena). AMD's 10h architecture will be used in both the desktop Phenom and the Barcelona (Opteron) quads. The architecture supports wider floating-point units, can fully retire three long instructions per cycle, and has virtual machine optimizations. While the design is solid, Intel will still be first to market with 45nm quads (the first AMD's will be 65nm). Do you think this architecture will help AMD regain the lead in its multicore battle with Intel?"

What?!

[rumith (983060)]

From the TFA:

However, the dual-core duel became, and remains a performance battle. AMD was widely perceived to have taken an initial lead. Intel was seen as recovering the advantage when its introduced its Core 2 Duo family in mid 1996.

Looks like it happened in a parallel universe.

Re:What?!

[LurkerXXX (667952)]

You must have brushed your teeth in a quantum mirror this morning.

Re:

[rumith (983060)]

Yes I did, and not only it's quantum, it also runs Linux.

Re:

[drinkypoo (153816)]

Core 2 Duo is faster in almost every situation than any dual AMD. But when you get up to 4 cores even, bus contention can be a problem. At 8 cores, intel is hopeless.

Hey Einstein

[p3d0 (42270)]

Take another look. He's making fun of the date they mentioned (1996).

Re:

[drinkypoo (153816)]

Yes, I saw it in that comment and others. However, I have learned to never assume that someone is doing something clever on slashdot. Usually one is disappointed.

Re:

[Nexum (516661)]

Queen Elizabeth II... is that you?

Re:Hey Einstein

[somersault (912633)]

I'm guessing it's QE I, or she would have said "two is disappointed".

Re:

[doubleofive (982704)]

In a universe where there existed a processor that could actually run Win95.

Sorry what?

[tomstdenis (446163)]

I had a 2P dual-core opteron 2.6GHz box as my workstation for several months. To be honest I couldn't really find a legitimate use for it. And I was running gentoo and doing a lot of my own OSS development [re: builds].

While I think quad-cores are important for the server rooms, I just don't see the business case for personal use. It'll just be more wasted energy. Now if you could fully shut off cores [not just gate off] when it's idle, then yeah, hey bring it on. But so long as they sit there wasting 20W per core or whatever at idle, it's just wasted power.

To get an idea of it, imagine turning on a CF lamp [in addition to the lighting you already have] and leave it on 24/7. Doesn't that seem just silly? Well that's what an idling core will look like. It's in addition to the existing processing power and just sits there wasting Watts.

Tom

Re:Sorry what?

[LurkerXXX (667952)]

Certain apps get a big boost from quad cores, lots of others don't. Some of those apps aren't for servers. For example, if you happen to do a ton of video editing, a quad core might be a good choice. I'll agree with you for most of us it's silly on the desktop right now. That won't necessarily be true in a few years when they write a lot more apps that need and take advantage of multithreading.

Re:

[CastrTroy (595695)]

Does multi-cores really help things like video rendering that much? Usually multicore means faster processor so yes it would help, but do you actually get better performance on 4x1GHz than you would on 1x4GHz? If not, then what you're actually looking for is a faster processor, not necessarily dual core. Servers need multiple cores because they are often fulfilling multiple requests at the same time. Desktops on the other hand are usually only doing 1 processor intensive thing at a time, and therefore,

Re:Sorry what?

[LurkerXXX (667952)]

That being said, it's a lot easier to get a 10 GHz computer with 4x2.5GHz CPUs, than it is to make a single 10 GHz CPU.

That's the entire answer right there.

Re:Sorry what?

[somersault (912633)]

Also your computer tends to be doing quite a lot in the background (especially with lots of 3rd party crapware/virus scanners/firewalls loaded onto it) rather than just running whatever app you currently want to be using. It's nice to be able to experience the full potential of one core in the app that you do want to use while leaving another core to handle background services, though I don't know if Windows automatically organises processor time to do that kind of thing, and I've never tried splitting my tasks over my 2 cores manually. I guess my system is nippier than my old single core one, though the thing is that you tend not to notice stuff that *isn't* there (ever got a shiny new graphics card and just been like "oh.. everything's the same but without the slowdowns!" .. can be kinda anticlimactic!)

Re:

[MrNemesis (587188)]

I'd be nice if things worked like that, but 90% of the time you're bottlenecked on I/O anyway (usually swapping due to insufficient memory to run all those craplets) and you're hard pressed to take advantage of one core, let alone four of the things. Of course, once everyone has their 1GB+ of RAM then SMP might get a better chance to shine...

I've been telling people not to bother buying fast processors for years now, unless I know they're heavily into their gaming or media editing. Every pound they don't sp

Re:

[tomstdenis (446163)]

Linux is aware of SMT, multi-core, SMP and combinations there of. It calcs migration costs for moving processes around and the like. For example, in a NUMA aware setup, it won't migrate a process to a different NUMA zone unless it has to. It does round-robin processes through cores though kinda like load-balancing [keeps the heat down too].

You can extract CPU info from the /sys dir, and use sched_setaffinity() to lock your threads to a given core if you want.

Tom

Re:

[robi2106 (464558)]

Oh yes. The improvement is easily more than double. I have a P4HT 3.xGHz alienware and a 2GHz T2700 Core 2 Duo made by Lenovo (IBM Thinkpad). Both have 2GB of RAM, though the Alienware has a RAID0 storage system.

But the Core 2 Duo is easily 2 times as fast to render AND is far superior when previewing video with lots of color correction or lots of layers of generated media (movie credits or text overlays are particularly harsh because of all the alpha blending for each source). The P4 system struggles t

Re:Sorry what?

[Applekid (993327)]

According to a writeup on HardOCP back in September, the new design features the ability to pretty much halt cores on-die and save power [hardocp.com]. (hit next a few times, I wish I could get my hands on the actual Powerpoint)

Re:Sorry what?

[TheThiefMaster (992038)]

My workstation is a core 2 quad, and a full debug build of our project takes 20 minutes, despite using a parallel compiler. On a single core it takes about an hour. You don't want to know how long the optimised build takes on one core.

So there are plenty of workstation uses for a quad core, but I agree that at the moment it's overkill for a home desktop.

less power

[twistedcubic (577194)]

Actually, I just got a 65W Athlon X2 4600+ from Newegg which uses less power than my current 6 year old Athlon XP 1800+. The motherboard (ECS w/ ATI 690G) I ordered supposedly is also energy efficient. I guess I could save $60 by getting a single core, but almost all single core Athlons are rated at more than 65W. Why buy a single core when it costs more long term and is slower when multi-tasking?

Re:

[TheThiefMaster (992038)]

Why's that a reply to me? I didn't mention power/heat.

Re:

[Chirs (87576)]

Heh...our full build takes about 6 hrs on a quad. Full kernel/rootfs built from scratch for 7 separate boards using 4 architectures.

Re:

[TheThiefMaster (992038)]

You're obviously working on something bigger than me then.

Mods, pay attention

[p3d0 (42270)]

Someone makes this same comment every time advances in CPU technology are mentioned.

Re:Sorry what?

[rrhal (88665)]

While I think quad-cores are important for the server rooms, I just don't see the business case for personal use. It'll just be more wasted energy. Now if you could fully shut off cores [not just gate off] when it's idle, then yeah, hey bring it on. But so long as they sit there wasting 20W per core or whatever at idle, it's just wasted power.

AMD's cool & quiet tech will shut down individual cores when you are not using them. I believe this is all new for the Barcelona. It idles down cores when you are not using them fully. It shuts off parts of cores that you aren't using (eg the FPU if you are only using integer instructions).

Uh...

[Per Abrahamsen (1397)]

I had a 2P dual-core opteron 2.6GHz box as my workstation for several months. To be honest I couldn't really find a legitimate use for it. And I was running gentoo and doing a lot of my own OSS development [re: builds].

Uh, doesn't "make -j 3" gives you a good speedup? I'd imagine multi-core being great for development, at least for compiled languages.

Re:

[Oddster (628633)]

I work in the games industry, and I assure you, the industry is moving towards taking full advantage of multi-core machines. In fact, the move is good, because it coincides well with the XBox 360 and the PS3 - the 360 has 3 hyper-threaded cores, with 5 hardware threads available for the game, and 1 for the OS. The PS3 has the central processor, and 7 coprocessors which all run independently. PC Hardware moving in this same parallelization direction makes life a little bit easier for game software develop

Re:

[Splab (574204)]

Future games will utilize more cores, one core for kinematics/animations, one for physics/collisions, one for AI and one to bind it all.

Re:Sorry what?

[ArsonSmith (13997)]

This is true, but as an EMACS user I find quad core to be a huge boost to my ability to edit text files at a respectable speed.

Why the fuss over 45nm?

[Smidge204 (605297)]

Ultimately, it's performance that makes a successful product, not gigahertz or nanometers.

Sure, the 45nm process has great potential for better performance and higher efficiency, just like faster clock speeds had great potential - until AMD made a better architecture and achieved better performance at a lower clock speed than Intel's offerings at the time.

Let's wait and see how it really performs before passing judgement.
=Smidge=

Re:Why the fuss over 45nm?

[by Anonymous Coward]

So what you're saying: size doesn't matter?

Re:

[Eukariote (881204)]

Indeed, let's wait for the benchmarks. I would like some more real-world and 64-bit benchmarks: most recent reviews seems to have studiously avoided those in favor of synthetic 32-bit only benchmarks that are not very representative and are easily skewed with processor-specific optimizations.

And I'm not sure going to 45nm process will allow Intel to step back ahead. It seems process improvements have been yielding diminishing results in performance related areas. Transistor density will go up, though, so

Support?

[Sorthum (123064)]

Quad core is all well and good, but are there really that many apps as of yet that can take advantage of it? TFA claims this is for servers and for desktops, and I'm not certain of its utility on the latter just yet...

Re:

[EvanED (569694)]

MAKE -j6.

Mmmmmmmm....

(-j6 instead of -j4 in an effort to counter I/O latencies... Actually that'd be an interesting benchmark; figure out what the optimum level of parallelism is. Too little and processors will be idle, too much and context switches would become an issue.)

Re:Support?

[Mr Z (6791)]

Prevailing wisdom and personal experience suggest using "-j N+1" for N CPUs. I have a 4 CPU setup at home (dual dual-core Opterons). Here's are approximate compile times for jzIntv + SDK-1600, [spatula-city.org] which altogether comprise about 80,000 lines of source:

• -j4: 6.72 seconds
• -j5: 6.55 seconds
• -j6: 6.58 seconds
• -j7: 6.59 seconds
• -j8: 6.69 seconds

Now keep in mind, everything was in cache, so disk activity didn't factor in much at all. But, for a typical disk, I imagine the difference between N+1 and N+2 to be largely a wash. N+1 seems to be the sweet spot if the build isn't competing with anything else. Larger increments might make sense if the build is competing with other tasks (large background batch jobs) or highly latent disks (NFS, etc). But for a local build on a personal workstation? N+1.

--Joe

Re:

[Mr Z (6791)]

Happy to. At various points, one or more of the processes will be blocked in I/O. With N+1 tasks running, there's a higher likelihood that all N CPUs will be busy, despite the occasional I/O waits in individual processes. With only N tasks running, an I/O wait directly translates into an idle CPU during that period.

--Joe

Re:

[homer_ca (144738)]

Photo and video editing parallelize nicely. Besides gaming, that's the only CPU intensive process that most home computers will run. On the gaming side, most games don't run any better on quad core, but Supreme Commander [hardocp.com] is one of the few that do.

Re:

[gravesb (967413)]

With consoles becoming multi-core, won't the video game industry have to learn how to better write games that take that into account? Before, most of their audience was single CPU computers (with a GPU of course) and consoles. However, now that most computers are multi, as are consoles, it seems like they have to better use that power. Of course, it may take a few years before they figure out the best way to do so, and apply it consistently.

Re:

[vertinox (846076)]

Quad core is all well and good, but are there really that many apps as of yet that can take advantage of it?

Maya 3D

Or any other 3d rendering software where every CPU cycle is used to the last drop.

But other than that I can't think of anything off the top of my head, but multi-cores is very important to these types of apps. It is the different between 12 and 6 hours waiting for the project to render then people will go with the 6 hours.

Re:

[QuasiEvil (74356)]

So I suppose whatever OS you're using only has one thread/process running at a time? I've never understood the argument that multi-core doesn't benefit the desktop user. As I look at my machine right now, I have two development environments going (one actually in debug), four browser windows, an email client, an IM client, various background junk (virus scanner, 802.1x client for the wireless), and of course the OS itself - XP. None of those needs a more powerful proc, but it's nice when they're all grab

Scalability, 64-bit, and FPU

[Eukariote (881204)]

When it comes to multi-processing scalability, AMD's Barcelone/10h/Phenm single-die four core with hypertransport inter-chip interconnects will do far better than the two-die four core shared-bus Intel chips. Also, both the old and new AMD architecture will do relatively better on 64-bit code than the Intel Core 2 architecture: Intel's micro-op fusion does not work work in 64-bit, and their 64-bit extensions are a relatively recent add on to the old Core architecture. The FPU power of the new 10h architecture will be excellent as well. On the other hand, Intel chips will remain very competitive on integer code, cache-happy benchmarks, particularly when run in 32-bit mode. Also, the SSE4 extensions of the upcoming 45nm Intel ships will help for encoding/decoding and some rendering applications, provided that the software has been properly optimized to take advantage of them.

Core 2 Duo?

[ratboy666 (104074)]

1996? Wow, have *I* been misled. Mid 1996 is the vintage of my Dual Pentium Pro 200Mhz, and I *really* thought that it was state-of-the-art.

Colour me disappointed...

Re:Begging the question

[tomstdenis (446163)]

In terms of market share, no. In terms of tech yes. See Opteron v. Intel P4 Xeon for example.

Tom

Re:

[Sorthum (123064)]

The problem is, analysts don't look at technology so much as they do market-share. The unfortunate battle between techies and beancounters wages on...

Re:Begging the question

[Chris Burke (6130)]

I introduce to you the Pentium D [wikipedia.org].

Re:

[Chris Burke (6130)]

Well it's not like anyone cared about the Pentium D, since it was pretty craptacular. Lessee, take a bandwidth-starved core design, slap two down in one package, downclock the system bus since the MCM has some of the same signal integrity issues as multi-socket, and you get... two cores that are starved for bandwidth even more. Yay.

So you were much better off waiting until Core 2 regardless, if you wanted an Intel dual core anyway.

Re:Begging the question

[gormanly (134067)]

Craptacular indeed (great new word) - the only thing craptacularer was the Celeron D they had out at the same time, which despite the name was not dual-core. Very amusing though, watching the 'tards with enough knowledge to be dangerous and who wanted a cheap PC,

"That one's a 'D', that's got 2 processors, that makes the internet faster"

Re:Begging the question

[homer_ca (144738)]

The Athlon X2 was superior to the Pentium D. It wasn't until Core 2 Duo that Intel took the lead in desktop CPUs.

Re:

[drinkypoo (153816)]

The original Core Duo led most benchmarks as well (I have a T2600 before me.) Core Duo is really an excellent design (made a nice change.)

Re:

[Eukariote (881204)]

They have a good chance. For one, their market share is rather higher than you make it out to be: about 20% of the 80x86 market vs Intel's 80%. Also, the computer manufacturers have an interest in keeping the competition between Intel and AMD alive. Unless they behave irrationally, they will help AMD to fully break the monopoly.

But the main thing that is pending for AMD is the antitrust lawsuit. Assuming there will be a just judgment, which is not a given with the US justice system led by the likes of Alb