rammodule

I have a Dell Poweredge R220 runnning on a 4GB 1RX8 PC3L 12800E-11-13-D1. If I add one 8GB 2RX8 PC3 12800E-11-13-E3 will it work...???

hello, i have a dell optiplex 990dt, recently one of the ram modules i have died i guess, the pc basically dose not turn on when that ram module is on it, so i assumed its dead, so im looking for a ram module of 8gb ddr3 and ive just noticed ram sticks have different voltages but i just cant...