Introduction

Friday afternoon we got an email pointing us to the latest beta driver from ATI. One of the key features of this driver is a performance boost for dual core systems. Building a driver to take advantage of parallel processing is quite a task, and extracting any noticeable performance gain out of it is even more difficult. So we are here today to see just what ATI has gotten out of their efforts thus far.

Admittedly, the highest performance gains come from low resolutions without antialiasing. It stands to reason that the more CPU limited a test is, the more benefit the game will get from freeing up CPU resources. The real benefit to end users if only lower resolutions benefit is questionable, but every step helps. With the future of computer hardware firmly planted in parallelism, the burden of improving performance shifts a little further towards software developers. Coming up with new and interesting ways to parallelize code efficiently is going to be quite a new task for desktop software programmers to tackle. And in the end, Amdahl's Law reminds us that we are still limited by the benefit we can get from parallelism. The percentage of code that must remain sequential will become the limiting factor. But every little bit of parallelization still helps.

There are really quite a few questions to be asked about this driver. After adding up everything we wanted to do, the sheer number of tests we had laid out was enormous. In an effort to be more efficient ourselves, we decided to break our analysis of the 5.12 driver up. This article is meant as a quick look at the benefits of ATI's dual core enhancements on a few select games running on X1K series hardware. We will compare this driver to the old one as well as dual core performance to single core performance.

Our next look at the 5.12 driver will include a comparison to NVIDIA performance in single and dual core systems, more than one ATI card, more games, and as many more things as we can pack in. Of course we are open to suggestion. But for now, we'll take a look at what we've got to work with.

The Test
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  • DrZoidberg - Wednesday, December 07, 2005 - link

    lol totally owned
    great link semiconductorslave

    heres another link took 5 secs to find since almost all the websites show AMD is better
    http://www.xbitlabs.com/articles/cpu/display/28cpu...">http://www.xbitlabs.com/articles/cpu/display/28cpu...
    Reply
  • porkster - Tuesday, December 06, 2005 - link

    You are failing to see that the majority of AMD CPU's are legacy as they have poor ability for modern software. Only AMD's top end CPU's are anything to consider, else all the others aren't suitable. AMD only perform well in single tasks. Intel are the KINGS of multitasking and bandwidth for the whole of their range.

    Games like DoD2 and Doom2 are not pushing the gfx routines and system, Black and White 2 does. B&w2 is a front line game, where the games in this test are safe bets for all processors. The point is this test was to measure performance for a dual-core device driver, so you would expect to see best of software.
    Reply
  • SemiconductorSlave - Tuesday, December 06, 2005 - link

    Well I'll agree that Hyperthreading benifits the P4 for multitasking, but lets not consider legacy, when comparing each companies latest dual cores, the Intel Pentium Processor Extreme Edition 840 $1029 at newegg, and the Athlon X2 4800+ $787 at newegg

    From Hardocp.com http://www.hardocp.com/article.html?art=NzY2">http://www.hardocp.com/article.html?art=NzY2

    AMD uses what they call Direct Connect architecture. Instead of two processor cores being saddled to one bus and run to a single memory controller as we see with Intel dual core technology, we have to remember that AMD Athlon 64 processors have the memory controller on the CPU die itself and therefore no “front side bus” is needed. So each CPU on our dual core X2 has a much quicker route to the memory controller as with current Athlon 64 processors.So still the biggest benefit to the entire K8 core system is shining through in AMD's Athlon X2 line in the ways of HyperTransport and its extremely wide bus width when compared to Intel’s dual core 800MHz bus.

    Sandra Memory Bandwith
    Intel EE 840 Dual Core 4331
    AMD X2 4800+ 5801
    From same article
    "On the dual core front, when you look at AMD’s flagship Athlon 64 X2 side by side with Intel’s flagship Pentium Extreme Edition 840 with HyperThreading, the obvious HyperThreading advantages seemingly disappear. In comparing single threaded applications, the Athlon 64 X2 4800+ shines over Intel’s 840 in our benchmarks."
    Reply
  • porkster - Tuesday, December 06, 2005 - link

    First off, sorry for spelling and typo's in last post. I reply on EDIT alot which this commenting system doesn't have, hehe.

    Ok, now I'm not bagging the X2 or AMD's top range as they are capable of doing the task required, but the for this test it's important to have Intel as the main test bed since it's got a higher threshold for things tested.

    Like I can't imagine games use all the sustained bandwidth yet, but a game playing whilst multitasking should put enough strain to show degradation in available memory data for game textures etc.

    If I'm correct from quick calcs, an AMD with top range DDR1 memory running a game at high refresh rates may only have 30meg bandwidth per game frame to play with. On the Intel that is about 55meg per frame. Now these sound like high values but when you consider multitasking and instance demands and gaming hi res textures etc, you start seeing the limitations.

    This test fails to test multitasking, it fails to place the strain of FRONTLINE games on the bus, it fails to compare the best of CPU's for the situation.
    Reply
  • porkster - Monday, December 05, 2005 - link

    If GFX drivers are going to start using multi core cpus and their threads then that will surely increase instance bandwidth on the memory bus, something Intel has trumphs over AMD.

    I hope the new dual core driver test compares the difference in bandwidth use and what effect that has between AMD and Intel based system.

    If you own a AMD without the top notch expensive ram then you maybe trapped is a past era as new games demand more bandiwdth and drivers start using more too.
    Reply
  • yacoub - Monday, December 05, 2005 - link

    So after looking at the charts it looks like if you use singlecore, stay away. Also no word on if they fixed the issue with FEAR that was mentioned last month as NOT being fixed in 5.11.

    On a side note: Anyone wonder if this is how they will start to push people from single to dual core? (That is, offering improvements for dc at the expense of sc performance.)
    Reply
  • wien - Monday, December 05, 2005 - link

    There's no other way of doing it really. Multi-threaded code will always run slower than the equivalent single-threaded code on a single-core CPU. (As long as you count threads waiting for disk-IO and stuff like that out of it that is.) If apps are ever to go the multi-threaded route, single-core performance will suffer... Reply
  • stephenbrooks - Monday, December 05, 2005 - link

    There's a thing called an "if" statement :) You can write "if (nprocessors>1) {/* Multithreaded code */} else {/* Single-threaded code */}". Reply
  • Questar - Monday, December 05, 2005 - link

    BS. There are many apps that are multithreaded that don't take a perf hit on a single cpu. Reply
  • yacoub - Monday, December 05, 2005 - link

    Is this the new Cat driver that fixes the FEAR.EXE bug? Reply

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