Sorry please ignore the troll above me.^
A 450W should be fine as long as it has the necessarily PCI-E connectors of the GPU.http://extreme.outervision.com/psucalculatorlite.jsp
Ok thanks for your reply. It does have PCI-E plugs so I'll buy a card and see how we go.
One more question:
My current RAM is a matched pair 800mhz 4-4-4-12. If I buy another matched pair, will it matter if I use standard 800mhz 5-5-5-18?