You also will need to take into considerating the older power supply, many of them do not provide sufficent amperage on the 12 volt line for the more powerful pci express cards because they conform to the older atx standards even if they're rated for xxx watts, any good power supply will have it's load capacites labled clearly on the side of it in a fashion similar to this
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fgamefaqspc.wikispaces.com%2Ffile%2Fview%2Fantectp650.png%2F218154268%2Fantectp650.png&t=665&c=Bxkhx_H5VW7cbg)
Due to inefficies of the netburst arcitecture, and dells usage of propriatairy power supplies in some models i would generally advise p4 at all and p4 dell especially