AMD Unleashed: Four CPUs, Two GPUs, All Overclocked

Benchmark Results: Crysis

3D Games: Crysis

With all four processors spaced within a fraction of a single frame per second (FPS), it’s clear that the GPU is the limitation at these demanding settings. Overclocking provides a slight boost, but still just a single frame separates the four processors.

Adding an even more demanding workload to the GPU (by enabling 4x anti-aliasing) results in a similar picture, except that the Athlon 7750 trails by a slightly larger margin at the lowest tested resolution. As the resolution is raised and performance dips into slide-show territory, the results are a bit unpredictable and less meaningful. 

It would almost seem as if the processor choice or overclocking were not very important in Crysis. But before jumping to such a conclusion, we need to take a look at more realistic playable detail settings for this level of graphics card.

At High details, we see the Phenom IIs shine, even at stock speeds, while the other two processors clearly benefit from overclocking. Raising the resolution again shifts to a GPU limitation and there is a need to further reduce some of detail options to Medium or Low to re-attain playable frame rates. 

These settings were not included in SBM charts, but have been run each month on the $625 system. In comparison, at 1280x1024, the Jan/Feb $625 PC achieved 38.35 FPS at stock speed and 50.55 FPS when overclocked. At 1680x1050, the $625 PC’s frame rate was 33.66 FPS at stock speed and 42.02 FPS when overclocked. 

Given the GPU limitations with a single Radeon HD 4870, adding a more powerful graphics card, such as the Radeon HD 4870 X2, greatly changes the results. Even overclocked, the Athlon 7750 BE isn’t capable of allowing playable frame rates at these Very High detail levels. In fact, only the two overclocked Phenom II processors were able to deliver playable performance up to a 1680x1050 resolution. 

The same trend continues with anti-aliasing applied, although even the mighty HD 4870 X2 will be limited to low resolutions at these settings.

While many gamers will drop resolution in order to crank up detail levels, others prefer to use the LCD’s native resolution and adjust detail levels as needed. If you're gaming at 1920x1200, the Radeon HD 4870 X2 handles DirectX 10 High details very well, but as seen here, you may need to overclock or even replace your CPU to attain acceptable performance.

By just looking at the two lower resolutions, one could falsely assume that, since performance drops when raising the resolution, even this graphics card must limit performance. But notice that performance at 1920x1200 is nearly identical (and sometimes even a tad higher) than at 1680x1050. This is a clear indication of a CPU limitation, and in this test the wider aspect ratio stresses the CPU more, causing the performance drop. To test this theory, we ran the stock Phenom II X4 940 BE though various other resolutions. 

Sure enough, the results indicate a CPU limitation and not a GPU limitation. The narrower the aspect ratio, the higher the performance, yet the number of pixels pushed had no effect on performance. Keep in mind that there are a lot of physics effects going on this Crysis bench, so this is not a blanket statement to apply toward all games. In fact, even the reverse could hold true in other titles. However, this also isn’t the first game in which we have seen CPU-limited settings that resulted in lower performance at wider aspect ratios. 

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  • waxdart
    I just skipped to the conclusion to see if reading the whole thing would be worth it.

    Seems to me like AMD know there stuff is slower and you have to accept that you have to overclock, Or their products have huge temperature problems at higher levels, so let’s "re-brand" it over clocking and let the punter spend X on cooling.

    How much goes into over clocking equipment Vs getting a CPU that runs faster and cooler in the first place? Is that much being saved?
    /Honest question with a hint of sarcasm.

    Also - I accept that just getting a system to over clock as much as possible is a valid waste of free time and good money as any other. If you enjoy it go for it.
  • wild9
    Phenom II X4 is good at stock speed compared to Intel (especially games like GTA IV), and overclocks quite well. Practically any CPU of this nature (both AMD and Intel), will require focus on keeping temps down if you want a decent overclock.