I dont know how to find out the socket all I know is what dell.com has listed under my serial number for what I had which is Processor, 80546, 2.8, 1M, Pentium4 Prescott Dt, 533, E0., Hard Drive, 80GB, I, 7.2K, 2MB WD-XL80SD-2, 512MB DDR SDRAM at 400M, 32X64 8K, 184