Lost Planet: Colonies
This game’s results are similar to those of Unreal Tournament 3: the single Radeon HD 5870 is quite satisfied with the junior quad-core CPU while the pair of such cards eagerly welcomes a powerful CPU with fast platform, boosting the average frame rate.
S.T.A.L.K.E.R.: Clear Sky
As you can see, you don’t have to worry about your CPU if you want to play S.T.A.L.K.E.R. on a single Radeon HD 5870 card. An Intel Core 2 Duo at 2.67GHz is more than enough for this game. It’s different with the CrossFireX configuration for which the overclocking of the Intel Core i7 is only unrewarding. The Core i7 platform is fast even at the default CPU frequency. As opposed to that, overclocking the Intel Core 2 Duo and AMD Phenom II X4 from 2.67 to 3.4GHz helps improve the average frame rate and get a considerable increase in the bottom speed. When the CPU frequency is increased from 3.4 to 4.1GHz, the speed grows up too, but not that much. This is only true for the resolution of 1280x1024 but there is little sense in playing S.T.A.L.K.E.R. at that resolution. When it comes to 1920x1200, overclocking is unrewarding.
Far Cry 2
Again, the single Radeon HD 5870 does not need an advanced processor. There is a performance growth at 1280x1024 with low-quality settings, but only on the Intel Core 2 Duo and at the first frequency of the AMD Phenom II X4 platform. The Intel Core i7 platform is always fast and the Radeon HD 5870 does not deliver better results in Far Cry 2 if you overclock the CPU.
The CrossFireX tests suggest that two Radeon HD 5870 cards can make a good use of a fast CPU. Save for the resolution of 1920x1200 at high-quality settings, the Intel Core i7 enjoys a hefty advantage over the two other CPUs. If you’ve got two Radeon HD 5870 and want to play Far Cry 2, you may want to consider upgrading your CPU.