X99 - RAM only works in slots 1 or 3

X99 - RAM only works in slots 1 or 3 ram slot 1 and 3 I noticed the RAM slots in my laptop have written over it STD in one slot and RVS in another slot When I put one new RAM in the STD slot and an ram slot 2 not working In this video, we have elaborately discussed which ram slots 1 3 vs 2 4 and different channel

ram slot 2 not working If you look at your RAM slots in the motherboard they are usually numbered 1-4 from the CPU outwards with the slot closest to the CPU being

ram slot 1 and 3 or 2 and 4 so my task manager said 1 of 2 ram slots used, when i hover it said slot 1: empty slot 2: 4,0GB, 1600mhz but it show 8gb of ram just fine  Yes, the 2009 4,1 & 201012 5,1 Mac Pro single Xeons use RAM in adjacent pairs [unlike the old 2008 3,1 which looks like a knitting pattern