does motherboard affect perfornce at anyway i have a asus P8H61-M LX and thinking of upgrading my grafic card to gtx660ti and psu to seasonic 620 w
plsss help guyz im not thinking about overclocking ,...............
Motherboards tend to not have a significant impact on gaming performance other than feature support and overclocking capability. Upgrading your motherboard shouldn't make a noticeable impact on your gaming experience unless you make use of some features on a newer board such as a board with Lucid HyperFormance and Virtual V-Sync.
Not to forget the overclocking capabilities, if you're going to OC, the motherboard is very important. If you're upgrading anyway and you really want to OC go for a Z77 motherboard, it's the best chipset for a motherboard that you can OC from. And don't forget, if your CPU isn't a 'K' model then don't expect much from overclocking or even don't upgrade at all because a motherboard can't provide much for performance except some new features that has nothing to do with gaming probably.
It will run fine. PCI-E 3.0 is the new standard, it is twice as fast as PCI-E 2.0. There are no graphics cards out right now that benefit from having PCI-E 3.0. Nothing out right now fully saturates PCI-E 2.0, so you will suffer no performance loss with putting a PCI-E 3.0 card into a PCI-E 2.0 slot.
Nowhere does the GTX 660 Ti say that it requires PCIe 3.0. It does not require it and will work with any and all generations of PCIe. PCIe 3.0 is simply the newest version that it supports. Like others have said, it will work in a system that only supports up to PCIe 2.0 and it won't affect performance much at all. Worst case scenario is that you have maybe 1% or 2% less performance and that is not noticeable by even the most sensitive gamers.