Closer Look at AMD Memory Performance

Now that we've shown AMD's Athlon 64 to be the CPU of choice for Half Life 2, let's have a closer look at the factors that influence Athlon 64 performance in Half Life 2.

Single Channel DDR400 vs. Dual Channel DDR400

The older Socket-754 Athlon 64s and the newer Socket-754 Sempron processors both only offer a 64-bit DDR400 memory interface, but how important is memory bandwidth to Half Life 2 performance? 

In the past we've seen that the Athlon 64 platform is not very sensitive to memory bandwidth, but that will obviously vary from one application to the next.  Let's see how Half Life 2 fares:

 
at_canals_08
at_coast_05
at_coast_12
at_prison_05
at_c17_12
128-bit
116.12
140.43
123.37
113.69
83.15
64-bit
113.44
130.18
118.32
110.58
74.63

Surprisingly enough, Half Life 2 is decently sensitive to memory bandwidth.  While GPU limited benchmarks like at_canals_08 show a mere 3% performance improvement, at_coast_05 and at_c17_12 in particular show a 7% and 12% performance improvement, respectively.

Dual Channel DDR400 vs. Dual Channel DDR333

Given what we've seen with 64-bit vs. 128-bit memory buses and Half Life 2, we'd expect DDR333 to have a reasonably large impact on performance, so let's find out:

at_canals_08
at_coast_05
at_coast_12
at_prison_05
at_c17_12
DDR400
116.12
140.43
123.37
113.69
83.15
DDR333
114.67
134.04
120.23
113.6
77.91

The largest differential between DDR400 and DDR333 is about 7%, and obviously if we were talking about a single channel memory setup the difference would be even greater.  Point?  More memory bandwidth is better for Half Life 2, that will mean even higher frame rates for overclockers.

AMD vs. Intel Performance Memory Latency Impact on Performance
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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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