I have an e6750 with a MSI systemboard with one PCI-e 16x slot on it right now, and a Sapphire HD2600xt with DDR2 800 corsair memory. What im trying to figure out is should i return the HD2600xt and get the HD2900xt? Or should i buy a new systemboard and crossfire the HD2600xt's? Getting the 2900 would be another $260 if i return the 2600, or i can get a decent Asus board and crossfire the 2600's for about $300 in the future. The thing is right now im really tight on money, so would the crossfired 2600 be a good upgrade or getting one HD2900xt?