I've been facing a similar situation. Trying to upgrade my 530s with a much better Pentium D 950 processor. The processor has not yet worked, and I have traced the problem to the lack of BIOS compatibility. Your dell desktop comes with a dell BIOS, which means a few things. A: it's unlikely that any processor that dell doesn't sell to you according to your model will work. B: You probably won't be able to flash the BIOS because dell has it locked. C: Even if you could flash the BIOS it's unlikely that it will work, because the G33M(02) motherboard (contained in the 530 desktop) sold directly by Foxconn is has been modified for/by Dell, meaning that the Foxconn G33M BIOS might not even work if you could flash it. I've only been researching this for a couple days I'm in the same boat as you, I don't know enough about the BIOS itself to make any solid conclusions. Right now it's looking like it's impossible.