We don’t have a clear picture here. The tested cards perform predictably at 1600x900 but then we see a queer thing at 1920x1080: the performance of the top-end model gets somewhat lower when we switch from the LGA1156/Core i5-750 to the LGA1366/Core i7-975 EE platform. This may be due to a negative effect of Hyper-Threading technology which is not supported by the Core i5-750, but we can also write it off as a measurement inaccuracy. The Core i5-750 platform suddenly slows down at 2560x1600 but this was due to the smaller amount of system memory: 4 gigabytes as opposed to 6 gigabytes on the LGA1366 platform.
The Nvidia cards show a similar effect. It is the GeForce GTX 275 at 1600x900 and the difference of 5% can hardly be only due to measurement inaccuracies. This effect does not show up at the higher resolutions where the GeForce series products perform in different ways. For example, the GeForce GTX 470 is 6% faster with the better CPU at 1920x1080 but does not benefit from the latter at 2560x1600 whereas the GeForce GTX 480 speeds up by 8% with the top-end CPU at the highest resolution. As opposed to the previous tests, the Nvidia cards are not very CPU-dependent, but they only deliver high speed at 1600x900 (and the bottom speed of the GeForce GTX 275 is too low to be comfortable even then). Oddly enough, the LGA1156 platform is quite satisfied with 4 gigabytes of system memory. We don’t see any performance slump at the highest resolution as with the AMD cards.
Far Cry 2
The junior graphics card in this review is obviously a bottleneck and its performance doesn’t depend much on the CPU and amount of system memory. The more advanced cards offer more headroom in choosing your CPU, especially at 1600x900 (but this resolution is unlikely to be used with top-end graphics cards). At the higher resolutions the Core i7-975 EE does not boost the frame rate more than 5%, so there is no sense to prefer it to the cheaper Core i7-920 if you’ve got an LGA1366 mainboard. And if you are building your computer from scratch, you may as well go the LGA1156 or even AMD AM3 platform, especially as both platforms offer more advanced processors than junior Core i5 or AMD Phenom II models.
The same is true for the Nvidia cards. We can only note that the GeForce GTX 470 proves to be the least CPU-dependent model in this test. That card is going to perform nicely in Far Cry 2 together with an affordable CPU, but you must be aware that it may only show its best with some more advanced CPUs than the Core i5-750.