I mean Bf3 makes use of the hyper thread feature on the 2600k/3770k/4770k, so it will handle large server load better than the 2500k. Wether or not its enough to make a big difference im not sure as ive only ever had HT on whilst Ive had bf3. On high servers I meant those big 64 player servers, not sure if it matters on 32man servers and below.
GTX 770 sli will put out more fps than a single gtx 780, however according to anadtech gpu bench a single gtx 770 already manages over 85FPS at 1080p on max settings, so unless your going over 1080p or using a 120hz monitor I dont think there would be much of a need for 770 sli.
Edited by $ilent - 7/1/13 at 10:28am