Hello Dell community,

I got a Dell Optiplex 780 SFF with 4 GB of DDR3 RAM, which i upgraded to 8, and now i would want to uprage to 16GB(that's the max. i can upgrade). I bought two Corsair 8GB DDR3-1333(PC3-10600)UDIM Rams, but when i put it inside and turn on my computer, no screen, and the computers fans are being loud. I get 3 and 4 green light error code, which means RAM error, but someone said that Crucial is 100% compatible with Dell? I don't know what to do, because I already swapped the RAM's to different slots, but nothing changed.