I just bought 2 8gig chips for my computer i have 16 gigs alrdy installed via 4x4 gig chips. When i went and installed the 8 gig chips in place of 2 of the 4 gig chips the computer did not boot. the lights on the mouse and keyboard did not light up screen stayed black. I tried to install just one 8 gig chip and to no luck still black screen tried in all 4 slots. so i put in one 4 gig chip and the damn thing booted so i installed the remaining 4 gig chips that i alrdy had before. my question is why can i not use the new 8 gig chips. they are the same brand and speed just more per chip .