So im building a new gaming rig and wondering if someone could recommend a good processor for a 680GTX SLI rig. I want to stick with an intel, as i have had bad luck with amd. Would an i5 be good enough? Or would I need a higher end i7 to prevent any CPU bottleneck?
No it doesn't as Intel i7 2nd gen does not support PCI-e 3.0. The cards would run in 2.0. The CPU just does not have the instructions and capabilities at all. 2500K/2600K/2700K can't do 3.0 ever period. You need a Z68/Z77 platform WITH an i7 3rd gen aka i7 3750/3770k. You can get a hack on SOME X79 boards paired with for example 3930K for 3.0 to work properly, but it's hit and miss. OP I hope this clears up any confusion and helps. For Xfire or SLI of any high end PCI-e 3.0 cards, you should have at least a 3570K and Z68 with 3.0 or a Z77 to get the best out of your cards.
Isn't the difference between PCI-e 2.0 and 3.0 like... 1 FPS? My 2500K @4.5ghz does just fine with my setup, except for BF3 MP which is highly CPU intensive (aiming for 120fps, I always get above 60 anyway).
When running sli you drop down to 8x/8x pci-e 3.0 which has the same band width as 16x/16x pci-e 2.0. Keep in mind this is disregarding mobo that have say a plx chip or the like to give you more pci lanes but those tend to add latency and the overall results are the same as just 8x/8x.
High end tri and quad gpus benefit the most from pci e 3.0. For a single card or 2 way sli pci e 2.0 is enough. OP the 680's love high clocked k model 1155 and 2011 cpu's
I owned 680SLI 2600k 5Ghz PCI-E 2.0 (16/16) and 3770k 4.7 SLI Runs-PCI-E 3.0 (8/8) no difference in FPS in any game. Even played CPU 3770k 4700MHzMB SLI Runs---PCI-E 3.0 (8/8) Physx Runs---PCI-E 3.0 (8/4/4) Pyhsx running PCI-E 2.0 No different in FPS. IF you do higher than 2560x1440 there may be a difference but I did not test that resolution. Even so 1920x1080 will give you higher FPS then compared to any resolution higher than anything above 1920x1080
For today's cards yes the FPS gains are minimal. 1-5 FPS on average for any given situation. But really if you are buying flagship 3.0 cards, then there is very little reason to buy a 2.0 cpu/board. May as well spend an extra 50 on 3.0 compliant parts.
This is a bonus of the x79 platform i get full 3.0 pcie x16 on each slot, but need to apply reg patch for the 3.0 to work