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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  • dderidex - Wednesday, February 02, 2005 - link

    Quick question...

    On the 'cache comparison' on page 5, where they compare an A64 with 1mb cache to an A64 with 512k cache...

    What CPUs are they comparing?

    512k Socket 754 (single channel)
    vs
    1mb Socket 754 (single channel

    or

    512k Socket 939 (dual channel)
    vs
    1mb Socket 939 (dual channel)

    or

    512k Socket 754 (single channel)
    vs
    1mb Socket 939 (dual channel)

    etc.

    No info is provided, so it's hard to really say what the numbers are showing.
    Reply
  • doughtree - Tuesday, September 06, 2005 - link

    great article, next game you should do is battlefield 2! Reply
  • dsorrent - Monday, January 31, 2005 - link

    How come in all of the CPU comparisons, the AMD FX-53 is left out of the comparisons? Reply
  • PsharkJF - Monday, January 31, 2005 - link

    That has no bearing to half-life. Nice job, fanboy. Reply
  • levicki - Saturday, January 29, 2005 - link

    Btw, I have Pentium 4 520 and 6600 GT card and I prefer that combo over AMD+ATI anytime. I had a chance to work on AMD and I didn't like it -- no hyperthreading = bad feeling when working with few things at once. With my P4 I can compress DVD to DivX and play Need For Speed Underground 2 without a hitch. I had ATI (Sapphire 9600 Pro) and didn't like that crap too especially when OpenGL and drivers are concerned = too much crashing.
    Intel .vs. AMD -- people can argue for ages about that but my 2 cents are that musicians using Pentium 4 with HT get 0.67 ms latency with latest beta kX drivers for Creative cards and AMD owners get close to 5.8 ms. From a developer point of view Intel is much better choice too due to great support, compiler and documentation. So my next CPU will be LGA775 with EM64T (I already have a compatible mainboard) and not AMD which by the way has troubles with Winchester cores failing Prime 95 at stock speed.
    Reply
  • Carfax - Saturday, January 29, 2005 - link

    Yeah, developers are so lazy that they will still use x87 for FP rather than SSE2, knowing that the latter will give better performance.

    Thats why the new 64-bit OS from MSoft will be a good thing. It will force developers to use SSE2/SSE3, because they have access to twice as many registers and the OS itself won't recognize x87 for 64-bit operations.
    Reply
  • Barneyk - Saturday, January 29, 2005 - link

    I would've liked to se some benchmarks on older CPUs to, kinda dissapointed... Reply
  • levicki - Friday, January 28, 2005 - link

    I just wonder how would this test look like if it was made with 6800 Ultra instead with ATI X850 XT.

    Disabling SSE/SSE2 on Athlon and getting the same results as if they were enabled means that game is NOT OPTIMIZED. Using FPU math instead of SSE/SSE2 today is a sin. It could have been 3-4 times faster if they cared about optimizing the code.
    Reply
  • Phantronius - Friday, January 28, 2005 - link

    #53

    Its because the Prescotts wern't better then the Northwoods to begin with, hence why don't see squat performance differences between them.
    Reply
  • maestroH - Friday, January 28, 2005 - link

    Thx for your reply #56. Apologies for false '@9700pro' statement. Meant to say 'soft-modded with Omega driver to 9700pro'. Cheers. Reply

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