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?"

Re:Begging the question

[tomstdenis]

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

Tom

Re:Begging the question

[homer_ca]

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:Begging the question

[Chris Burke]

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

Re:Sorry what?

[Applekid]

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:Support?

[homer_ca]

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:Sorry what?

[TheThiefMaster]

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.

Hey Einstein

[p3d0]

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

Re:Sorry what?

[rrhal]

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).

Re:Watch the pretty assistant while....

[Eukariote]

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 Alberto Gonzales, a multi-billion dollar compensation for anti-competitive practices will fall to AMD. They have enough debt financing to last until then.

Re:Yeah, but when can I buy quadcores from AMD?

[DrMrLordX]

You might be able to get them in Q4 2007 [wikipedia.org]. With launch dates of August 2007, we'll probably see the actual chips in retail channels by October. OEMs/builders should have products featuring the new Opterons much earlier.

Re:Support?

[Mr Z]

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:AMD IS Doomed to Always Be a Follower Unless...

[Anonymous Coward]

wait.. What? AMD is following Intel? Mind telling me how that is exactly? IIRC, both Intel and AMD are using the 64 bit extensions that... guess who... AMD made on their Athlon 64 processors first. Also, AMD was first to move their processors away from a shared BUS. The reason why they say their processors are "True" dual or quad core is because their architecture was designed better to scale. Take a look at the multi processor benchmarks compared to netburst, and even take a look at how much better AMD processors today scale with the number of cores compared to Intel's lineup.

Following? Hardly.

Uh...

[Per Abrahamsen]

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:AMD IS Doomed to Always Be a Follower Unless...

[Anonymous Coward]

Don't follow the link, he's just a click whore. And completely off-topic by the way.

Re:Sorry what?

[Oddster]

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 developers, because we can use similar software architecture now for both the HD consoles and the PC.

Expect the first mass-market software that takes advantage of these processors to really start picking up within the next 12-24 months in the games industry. In fact, I do believe that FEAR was one of the first PC games built with MT in mind, and I'd wager that you can see significant performance differences with that game between a single and dual core PC.

Re:Support?

[Mr Z]

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