I5 2500k CPU not compatible with PCIe 3.0???

I was on NewEgg.com and was reading a review on the Intel i5 2500k. One of the reviews said that it wasn’t compatible with PCIe 3.0 GPU's. I don’t know why this would happen, maybe the newer cards aren’t backwards compatible with older CPU's, and they don’t play well together.

ATM i have a 550ti, and if i was to get a processor upgrade, the 550ti would be the weakest part of my system, and I was thinking of saving up my money for a gtx 670 or maybe a AMD hd 7970 in a year or two. So it I got this processor, would I have to stick to PCIe 2.0 cards, since the CPU isn’t compatible with PCIe 3.0?

Also, since they are the same price, if I got an i5 3570k would I be able to use PCIe 3.0 cards, since that CPU is newer?

Or if I want to eventually upgrade to a PCIe 3.0, would I have to get an i7?

In other words...

1) Is an i5 2500k compatible with PCIe 3.0 cards?
2) If it isn’t, is a i5 3570k compatible?
3) if not, do I have go to i7 CPU for PCIe 3.0 compatibility?
4) If yes, which i7 CPU should I go for overclocking and a price of ~ 220$

It’s a lot of information. This might be a stupid question because CPU and GPU are different things altogether. I just viewed the post and got worried, and want to be smart about thsi. I just want to upgrade my computer so that in a year or two I only have to buy what I want, and not something else along with it, like I have had to do previously.

Thanks!