Originally Posted by Zaid
so i was planning to upgrade my cpu/mobo/ram this holiday. i7-2600k seemed like a good upgrade, and then in march i was planning to get the 7970 CF. the issue i see here is the PCIe. the 7xxx series is suppose to use PCIe 3.0, but the i7-2600k only support pcie 2.0. would it cause any performance loss if i were to run 7970 CF on pcie 2.0(@ x16,x8)?
and yes, i do plan to overclock everything to its limits.
PCIe 2.0, 2.1 & 3.0 are all backward and forward compatible. Performance wise there shouldn't be effected, if any. Maybe it will, if the performance of a 7970 = 2x 6990s (4 GPUs).
Look at this way, a 6990 is actually 2x 6970 GPU core in one PCB. If you put the 6990 in PCIe2.0 x16, run a benchmark then compared it to the result of 2x 6970 sit in 2x PCIe2.0 x16/x16. Clock per clock the difference is neglibile, is any.
The above is not a good example but it's basically it. PCIe 3.0 will improve efficiency and minimize latency. By how much? Not seing any real test so far, only theoretical numbers.