Not likely. The Intel 3420 chipset doesn't support any i-series processors, but Dell supports only the i3 500-series processors, meaning support for those processors were specifically added to the BIOS, which also means that if Dell did not add support for the i5 and/or i7, then they will not work.  The only supported quad-core CPU's are the Xeon 3400-series (3426 and above).
Ok, I have a Poweredge R310 that came with a Pentium G6950. I want to upgrade it to a Quad Core. The socket is an 1156, and I noticed that the Core i5-750 is within my price range and has uses the same socket 1156.   Can anyone help me to make sure my Motherboard will support this processor?
Upgrade CPU in R310