I'm building a new system. So far I think I narrowed it down to Gigabyte GA-Z77X-UD5H (Z77 Ivy Bridge chipset) motherboard.
I was planning to get i5-3570K(Ivy Bridge) cpu, but now I can get i7-2600K(Sandy Bridge) cpu for free.
It is my understanding that Ivy Bridge platform brings support for PCIe3 and (additional?)USB3 ports. If I were to put SB cpu into IB motherboard, what is going to happen to PCIe3 slot? Will it not work at all or downgrade to PCIe2? Also, what is the situation with USB3 ports?