Alright, first results from the
3D Speed Machine benchmark:
i7 920 @ 2.66Ghz (1st gen i7, Desktop): 12 minutes 18 seconds
i7-2630 @ 2.0Ghz (2nd gen i7, Laptop): 11 minutes 57 seconds
Yes, that's right, the 2nd gen laptop CPU with lower clock speed beats my 1st gen desktop with higher clock. It's a surprising and promising result, but it needs to be taken with a grain of salt, there are some caveats.
First off if you visit the link above you'll notice that my i7 920 score is much lower than the other 3 there. I'm pretty sure that at least 1 of those, if not 2, are for overclocked CPUs, but the 10m33s time is for a stock CPU I think and my i7 920 is still not doing anywhere near that, which may indicate some kind of system bottleneck here. I'll be looking into it.
Second, the 3D Speed Machine benchmark that I created has always had a part of it that does not respond well to multithreading. The lower-right corner of the scene is actually where a good portion of render time is spent as it has the furthest depth to draw, interreflection between the reflective sphere and the water, and the densest parts of the plant population. This was done intentionally because at the time multi-core CPUs weren't all you could get, not to mention that not all TG scenes can be as efficiently multithreaded as we would like. So the idea was to have the majority of the screen area be rendered multithreaded, and then have a portion of render time be largely single threaded to sort of balance it out. Whether it is effective at its intended goal is another question, but the important consideration is that both the i7s here would have been working with 1 or at most 2 threads in that area for several minutes. Here's where an improved feature of the 2nd gen i7 comes in. While the CPU core clock is 2.0Ghz, it has TurboBoost which can clock it up to 2.9Ghz. Now the i7 920 has this too and its max turbo frequency is the same but given the other architectural improvements that show clock-for-clock that the 2nd gen i7 beats the previous generation, it makes sense that the slower CPU could pull ahead here.
All this being said I still have more testing to do. I will be trying a more multithreading-friendly scene, which should remove some of the i7-2630's advantage from turboboost. I will also be trying to downclock my 920 to match the 2630. More to come...
- Oshyan