AMD vs. Intel - Clock for Clock

Now it's time to tackle the touchy subject: how do AMD and Intel stack up to one another? First off, let's look at identical clock speeds to compare architectures.

Clock for Clock Comparison - DM-ShangriLa

Clock for Clock Comparison - DM-HeatRay

Clock for Clock Comparison - vCTF-Suspense 

At 3.0GHz, granted at a CPU-bound resolution, Intel holds a 26 - 31% performance advantage over AMD. Intel's Core 2 processors have historically done better clock for clock than AMD's K8, so it's not too much of a surprise, but an important mark in the sand.

We then cranked up the resolution to 1920 x 1200, and increased the world detail slider up to 5 to give us a more realistic situation for this clock speed comparison. The results were a bit surprising:

GPU Bound CPU Comparison - DM-ShangriLa

GPU Bound CPU Comparison - DM-HeatRay

GPU Bound CPU Comparison - vCTF-Suspense  

Despite being a mostly GPU-bound scenario, Intel still managed a 9% performance advantage over AMD at 3.0GHz. We suspect that there's something fishy going on as the test is quite GPU-bound, yet going from Intel to AMD yields a reasonable performance drop.

We looked at a 3.0GHz Athlon 64 X2 and compared it to its closest Intel price competitor, the Core 2 Duo E6550 (2.33GHz) at our high res settings:

The Intel performance advantage drops to 7% on average, but it's much larger than it should be given that we're dealing with a GPU-bound scenario. Note that difference between 2.33GHz and 3.0GHz on Intel is next to nothing, thus proving the GPU-limited case, so we're either dealing with an Unreal Engine 3 issue related to either the AMD CPUs or the nForce 590 SLI chipset/drivers we used. We've let Epic know, but for now it looks like UT3 definitely prefers Intel's Core 2, even when GPU-bound.

Who Cares about Clock Speeds? Overall CPU Comparison
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  • decalpha - Wednesday, October 17, 2007 - link

    Why not compare the CPUs with similar cache size, since Athlon 64 X2 6000 has 2MB cache whereas the Core 2 Duo E6850 has 4MB and cache size does seem to matter.
  • drebo - Wednesday, October 17, 2007 - link

    I think it's even more relevant to point out that clock-for-clock comparisons have been worthless for a very long time, and only seem to have come back on this site now that Intel has a more efficient pipeline.
  • PrinceGaz - Wednesday, October 17, 2007 - link

    The X2 6000+ actually has 2x 1MB cache, which in most cases is worse than 2MB shared, so the cache situation is even worse for AMD in the comparison that was performed.
  • drebo - Thursday, October 18, 2007 - link

    Well, cache size in general is less important for AMD processors, as the path from CPU to RAM is much, much quicker. It would be interesting (and very, very difficult to gauge) what the difference would be. This is most likely why they left AMD off of the cache comparison charts. It's impossible, due to far too dissimilar architectures, to isolate ONLY the memory subsystems, which is what a cache comparison would be attempting to do.

    Cache misses on an Intel architecture are far more expensive than on AMD's architecture. But, without otherwise identical chips, there's simply no way to make a comparison.
  • bloc - Wednesday, October 17, 2007 - link

    I think if you compared the 8600 gts and x2600 xt, the perf would be pretty close, with the x2600 xt being $50 cheaper.

    The architecture is there. Some games like cod4 hasn't taken advantage of it yet.
  • ImmortalZ - Wednesday, October 17, 2007 - link

    The second set of graphs on page 3 seem to be all confused. Mixed up title text?

    Also, regarding the ATI midrange part, surely you guys have heard about the 2900PRO?
  • JarredWalton - Wednesday, October 17, 2007 - link

    P3 graphs fixed. I'd imagine trying to get a 2900 Pro for testing is proving more difficult than anticipated. I know looking online that the few places I've seen that list them are out of stock.
  • ImmortalZ - Wednesday, October 17, 2007 - link

    Well, it's easy to test a 2900PRO. Underclock a 2900XT to 600Mhz core and 1600Mhz memory and test away! :D (there are 512MB GDDR3 and 1GB GDDR4 versions, so...). Just change the price from 389.99 to 249.99 for the 512MB and 319.99 for the 1GB.

    Of course, I'd personally wait for the 2950s to show up - single slot coolers are teh win :P
  • Bremen7000 - Wednesday, October 17, 2007 - link

    What about the page 6 graphs? Am I missing something or are they lacking something?
  • RobberBaron - Wednesday, October 17, 2007 - link

    Second that. The second set of charts on page 6 is Intel CPu's only. Little confusing

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