I resently purchased a MSI 8600Gts OC and while it has some good preformance now I know by late this year it will need more power if the games promised are on there way..Im upgrading mobo and ram and cpu soon and was considering getting an SLI mobo and add another 8600gts to run SLI for a cheaper alternative to a 8800. My first question is..Do i need the same brand 8600gts? or can I use any 8600gts..my 2nd is do i HAVE to have a SLI supported PSU and would 470w PSU be enough to power this?