JdL wrote:One thing I might add to this thread is that BF2 / BF3 is very multi-threaded. You are likely to benefit from a lower clock + more threads than you would from a higher clock + fewer threads.
The Intel i5 has 4 cores / 4 threads, whereas the i7 has 4 cores / 8 threads.
I'd wonder about this myself, a little, but I'm relying on my previous experience with hyperthreading- and basic understanding of how it works. Remember that Intel's P6 architecture (dating back to the Pentium Pro; yeah we're still using it!) doesn't have multiple FPU units per core, like AMD's K8. Rather, it relies on it's SSE2 capability (I know it's SSE4 or 4.1 or something, but those aren't the instructions being used here) in order to supercharge float operations. This works because Netburst (the Pentium4 family) had even crappier raw FPU performance, and for five or six years there everyone had to learn to code for SSE2, or risk their stuff basically not working on Intel.
So here's the thing. Whether or not hyperthreading provides a performance boost depends on the type of workload an application presents to the CPU. In the case of Battlefield games, particularly Bad Company 2 in a multiplayer environment, the CPU is saturated with float- most likely SSE2 type stuff related to the massive amount of coordination as well as the tremendous amount of physics work that needs to be done. Intel CPUs cannot handle more than one SSE2 thread per core. So, hyperthreading is only going to help if some integer heavy workload is also running on these cores. While there most certainly is some, like OS, AV/Firewall, and networking overhead to name a few, the real percentage that this presents is very low; I'd hazard less than 1% of a fast CPU like Intel's new quad cores.
The detriment of hyperthreading here is that with eight assignable cores, you are now trying to run eight SSE operations on four SSE units. Because there is overhead and L1 and L2 cache requirements for those extra threads, this can actually reduce performance!
Because hyperthreading isn't terribly suited for games, and because the 2600k is ~$100 more, it's very hard to recommend over the 2500k, given that they'll also both overclock to ~4.5GHz+ on air out of the box. Whatever small performance increase hyperthreading might provide simply isn't worth $100.