Cache Size Impact on Performance

As we continue to look at the Athlon 64 platform with respect to Half Life 2 performance it's now time to find out how much benefit the 1MB L2 Athlon 64s gain over the 512KB L2 parts. 

Given that we've already shown Half Life 2 to be sensitive to both memory bandwidth and latency on the platform, we wouldn't be too surprised to see some pretty big differences between 512KB and 1MB L2 Athlon 64 processors.

at_canals_08
at_coast_05
at_coast_12
at_prison_05
at_c17_12
1MB L2
116.69
134.45
121.67
118.51
80.39
512KB L2
111.56
126.2
117.35
115.75
74.14

With a performance advantage as large as 8%, the 1MB Athlon 64s (and Athlon 64 FXs)  do surprisingly well under Half Life 2 when compared to their normally competitive 512KB counterparts.  While 8% alone isn't much, combine that with the advantage of a 128-bit DDR memory bus and the Socket-939 Athlon 64 platform can offer a reasonably high performance improvement over even the Socket-754 solutions. 

SSE/SSE2 Impact on Performance

Just for kicks we turned off the Athlon 64's SSE/SSE2 instruction set support to see if that impacted performance in any way:

at_canals_08
at_coast_05
at_coast_12
at_prison_05
at_c17_12
SSE/SSE2 Enabled
116.12
140.43
123.37
113.69
83.15
SSE/SSE2 Disabled
117.64
140.94
125.85
116.55
82.56

Despite minor variations in performance, it doesn't look like SSE/SSE2 is doing much for the Athlon 64 under Half Life 2.  We just had to fulfill our curiosities. 

Memory Latency Impact on Performance High End Graphics Card CPU Scaling
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  • Roooooooooooooooooot - Wednesday, January 26, 2005 - link


    Ommmmm ... yes, a very nice article :)

    More than any article I've seen, this one made the point about the power of AMD processors for 3D gaming.

    "Megahertz Shmegahertz" could have been the title. The 3.8 Pentium running neck and neck with a 2 GHz AMD CPU. Now I understand !!

    One place I worked had hundreds of Dell Workstations. They gave us dual xeon ultra-SCSI jobbies. It may not sound like much, but 2 1 GHz Xeon's with an 18 Gig U160 or was it 320 SCSI HDD and an ATI FireGL graphics card was what I had.

    I would love to see an article about corporate CAD machines, AMD vs. Intel with various scales of video cards.
    Reply
  • bamacre - Wednesday, January 26, 2005 - link

    1,000,001 demands for A XP benchies, how about one for high-end Northwood P4's ?? Please? Reply
  • AkumaX - Wednesday, January 26, 2005 - link

    I one MEELIONTH the motion, i wish there were a XP barton benchmark somewhere in there, not just w/ the XP3200 (2.2ghz) but also w/ 2.3ghz and 2.4ghz (since most of us appear to also be running o/ced mobiles :P) Reply
  • michael2k - Wednesday, January 26, 2005 - link

    What did you expect? People were demanding the HL2 CPU article in the Mac threads... and lo and behold, the next day, Anand has posted the HL2 CPU article.

    You can either get something now, or you can get something finished... very rarely can you get both :)
    Reply
  • Crassus - Wednesday, January 26, 2005 - link

    I was also quite surprised that the article still appeared. I'm glad it did, but I think it falls short of Anandtechs high standard:

    1. For comparison, at least two AXP (two to see how it scales) should be in the test field
    2. As previously mentioned, Processor/speed/cache/socket. There is more that just one Athlon 64 3000+
    3. Including CAS 2,5 would have been nice as this seems to be the default for people using mainstream DDR3200 RAM
    4. What's the deal with the Athlon 3500+ in diagramm 3 on page 2?

    Something else bothered me:
    Quote: "If you are stuck with one of those older but still well-performing GPUs, don't bother upgrading your CPU unless it's something slower than a 2.4GHz Pentium 4 - you'd be much better served by waiting and upgrading to dual core later on."
    Common wisdom seemed to be that especially games don't take advantage of multi-threading. Do you have any new information that upcoming games are geared more towards multiple CPUs/cores/HT?
    Reply
  • quanta - Wednesday, January 26, 2005 - link

    The test didn't show the impact of using partial precision vs full precision on NVIDIA cards. As some people have mentioned[1], Half-Life 2 doesn't need full 32-bit precision to run smoothly. In effect, NVIDIA card is running in speed crippled by the game's designers.

    [1] http://3dgpu.com/archives/2004/12/01/boost-perform...
    Reply
  • DavidHull - Wednesday, January 26, 2005 - link

    I second the need for SLI configurations to be included, as many reviewers have found them to be extremely limited by the CPU. Reply
  • AtaStrumf - Wednesday, January 26, 2005 - link

    Interactive 3D charts in flash. Khm,... can it be done? Reply
  • AtaStrumf - Wednesday, January 26, 2005 - link

    I was starting to think this article has been bined, but fortunately it wasn't.

    First of all I agree with the need for an AXP 3200+ in the charts. It's still a very, very common PCU!

    Secondly this is only an OK article by Anand's standards. The first thing that really bothered me was how the CPU's are marked by some very long but also very useless names, like

    AMD Athlon 64 3400+ (2.4 GHz)
    Intel Pentium 4 570 (3.8 GHz)

    This takes a lot of room on the carts but still tells me nothing about Cache size or Socket type. I suggest names like:

    A64 3400+/S754/512kB/2.4GHz (its shorter and says a lot more)
    Same thing for Intel: P4 570/Socket/Cache...


    And how in the hell did you come up with CAS3? Most DDR 400 RAM (excluding OEMs) is CAS 2,5 and not 3 or 2. I appreciate the memory tests very much though, I just regret the very basic mistake in the underlaying assumptions.

    I understand it was a low priority, seriously delayed article, but I just can't shake the feeling it could have been so much more.

    One of these days I'm gonna have to take some time and put together a demo of how data is properly presented.
    Reply
  • Questar - Wednesday, January 26, 2005 - link

    "Next let’s take a look at at_coast_05, another very GPU limited test that has a good deal of NPC interaction as well as GPU limiting elements:
    "

    How the hell could this be GPU limited if the difference from top to bottom of the graph is > 50%?
    Reply

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