As well as testing a variety of cards on BF3's Frostbite 2 engine, we also wanted to investigate the effect of CPU clock speeds, the number of CPU cores and the effect of Hyper-Threading. Would an overclocked CPU help? Or could an ageing dual-core chip limp along? We under-clocked our Intel i7 965 CPU, as well as disabling two of its cores and Hyper-Threading, in order to find out. The results were surprising.
It didn't matter whether the CPU was running at 3.2GHz, 3GHz or even 2GHz; our benchmarks returned the same results. Even when we dropped the CPU down from four cores to only two, the in-game frame rates proved annoyingly stubborn. While BF3 will load itself across all four CPU cores when presented with a quad-core CPU, it seems to have little benefit when it comes to performance, running just as well with much lower clock speeds, or on a dual-core CPU.
Click to enlarge - There's no performance difference between a quad core CPU with Hyper-Threading and a similarly clocked dual-core chip
We also repeated the test by running our benchmark with 6GB, 4GB and even 2GB of DDR3 memory fitted into the system. Again, we found that performance remained stoically unchanged; only a single-core setup saw any difference, when the game flat-out refused to run at all. Needless to say, then, that BF3 appears to not be the most CPU-taxing game, instead relying almost entirely on the performance of the graphics card.