Guys, I am currently running GTX 770's in SLI on a Z68 mobo with a 2500K. Is there any chance that my cards are being bottle necked by only running PCIE 2.0 or would it be worth upgrading to an Ivybridge so I can activate 3.0 on my board?? Cheers. Sent from my HTC One using Tapatalk
Depends on lanes per card 8x8x8x would not. 8x8x4x would. Really does depend on motherboard as some z68 boards have chips added on that increase the pcie lanes. If your really going after tri SLI or cfx you either need one of those boards with the chip on or socket 2011 stuff which supports more pcie lanes. PLX chip it's an expensive addition though for most mobos.
you'd still see a small benefit with 3 cards over 2 (in some games) on Z68, but you'd see a larger performance gain with more PCI-E lanes PCI-E 2.0 vs 3.0 difference is minimal with 3 cards you're better off with X79, PLX doesn't really do anything
You can also find some more extreme motherboards such as the ASUS Maximus Extreme VI supports Tri SLI @ x8/x16/x8 V.s. 8x8x4 you'll see on lower end motherboards due to most run PCI-E 2.0 for their 3rd PCI lane. As far as PCI bandwidth on a 3rd 2.0 when the 2 primary's are 2.0 I'm not sure. I would still assume it would be x8x8x4 or x8x4x4 in which you would see bottle-necking