hi, im looking to upgrade my gaming pc so that i can run GW2 at 60 fps. i can run every other game at perfect fps except GW2. im looking to upgrade my mobo, if i have to, from a cheap $70 MSI to the Sabertooth 990FX. my current cpu is the FX 6300. as for my gpu its a 7870. i play on a 1600x900 resolution monitor and i have 8GB DDR3 RAM (wont upgrade it). i have a corsair 600w psu. my question is, should i crossfire my 7870 or buy a singleton gpu like a 7950 or 7970? also should i upgrade my cpu as well or my psu? please help, many thanks