The Dell Poweredge R420 processor upgrade kits or second additional processor uses the Intel E5-2400 and E5-2400 V2 series processors. The Dell Poweredge R420 is dual processor capable machine. Each processor supports six memory slots. If you are installing a second processor in your Poweredge R420 you can find the heatsink under Poweredge R420 heatsinks. If you have any questions on processor upgrades give us a call at 952-831-1032.