Scaling with Cores, Threads, and CPU Clock Frequency
Much has been made of SPECviewperf 12’s platform independence by the parties involved in its design. Instead, the benchmark's focus is decidedly on GPU performance. Still, running software on different systems never yields the exact same results, making it harder to relate our test results to all of the workstations out there requiring a new professional graphics card.
The critics who say our reference machine's 4.5 GHz Core i7 isn't representative of a real workstation might have a point. But using the aggressively-overclocked CPU was necessary to assure every score we generated was directly attributable to the cards we were benchmarking. That's a particularly important point when you're talking about similar-performing boards with big price tags. A slower CPU can quickly become a bottleneck, pushing small differences into the margin of error range.
Nevertheless, we still thought it'd be prudent to gauge the real effect of platform performance. To keep the exercise reasonable, we compared two cores and two threads to four cores and eight threads using 3.0, 3.5, 4.0, and 4.5 GHz frequencies. AMD's FirePro W7000 remained a constant, giving us the rendering power of an upper-mid-range graphics card priced under $1000. Even though high-end GPUs become processor-limited most quickly, the benchmark results can still get interesting in some applications, even with the board we used.
Both Creo 2 and Maya 2013 stand out from our first set of numbers. The two applications scale noticeably based on clock rate. Core and thread count matter less in Creo 2 at a given frequency, but Maya 2013 wants to run on a quad-core machine. On the other hand, CATIA and energy-01, the first of two volume rendering benchmarks, aren’t overly sensitive to CPU performance. Still, we can see that they don't perform quite as well with only two cores, two threads, and a 3 GHz clock rate.
In the second set of our scaling results, only SolidWorks responds to CPU frequency. Core and thread count don't make a difference. All of the other tests (medical-01, Showcase, and NX 8.0) are truly independent of platform performance, as revealed by their extremely uniform results.