Motherboard and RAM compatible

Buying new computer.
motherboard - EVGA, s. 775, 780i SLI ESA, NVIDIA nForce 780i SLI
RAM - X2 - DDR 2, PC-6400, 800 MHz, GEIL VALUE

I looked on nVidias,Evgas and Geils sites and nowhere it says that my ram are compatible with my motherboard.

Can someone with more experience tell does my RAM need to be compatible with motherboard? I looked on nVidia site and they say that ram must be compatible with their nForce 780i(not helpful).

I have the 790i from Evga and it is damn picky about the ram. I'm not sure about the 780i, but tbh I would expect to have to buy new memory. You might not have to, but prepare for the worst.

If you don't want to buy new memory, then I'd choose another board to be safe.