PSI Express 3.0 vs 3.0 x 16 and Memory

[Expired Oatmeal]

I've been looking at CPUs for an up and coming build (my first, so its budget). I've been browsing the 650s and I've noticed two things I could use answers on. The cards either come with "PSI Express 3.0" or "PSI Express 3.0 x 16".

Are these interfaces the same or different?

Also, will PSI 3.0/ x 16 work in a PSI 2.0 x16 slot on a motherboard?

Along with the PSI Express options, I've also come across cards with 1-2GBs. How much effect does the extra memory have on the card, and is it worth the extra money?

 

[RealBeast]

I think that you mean PCI Express. Yes the 2.0 and 3.0 cards and slots are fully interchangeable, you can get any card and any board and they will work together fine. There are no current cards that max out the 2.0 slot so it is not an issue yet. All of the single cards you find for 2.0 or 3.0 will be PCIe x16.

With most motherboards if you use two PCIe x16 cards, the slots revert to x8, but that too is not yet noticeable in performance.

More video memory is better for many games, especially games like BF4. I would try to get a 2GB card since it makes a difference in many games.