It's not really the processor that has to be compatible with the GPU, The motherboard and what type expansion slots are available on it. There are 3 main types of slots, PCI, PCI-E, and AGP. The Graphics card has to be matched to the slot in order to work. You can't put an AGP card in a PCI-E (or PCI) slot and vice-versa. If you could list the Dell model number of your PC, we could better recommend a solution for you.