PCI 2.0 bottleneck for new cards

[zuka__]

i have a I7 3930k witch PCI 2.0 board ... my currnet card is 970 ) plan to upgrade to 1070 ) i saw benchmarks with 980 and there was only 1-2% difference between 3.0 and 2.0 16x slots ... so with 1000 series there will be more difference or same story?

 

[RobCrezz]

Its not a problem, 1-2%.

 

[Rookie_MIB]

Agreed. Slight difference, probably not enough to notice. Think it out logically, ssuming that you're using only a single card:

PCIe x16 v 3.0 has enough bandwidth for two GTX 1080s and each one runs in x8 mode. So - each card gets 1/2 the bandwidth of a PCIe x16 3.0 slot.

PCIe x16 v 2.0 has half the bandwidth of v3.0. You're not running SLI, so the card runs in x16 mode.

Since a GTX 1080 can run then in x8 v3, the x16 v2 is equivalent in bandwidth, so the slot won't bottleneck the card in any appreciable way.