Second ram slot not doesn't work

Second ram slot not doesn't work ram slot 1 and 3 Note a little more testing today shows that it works with RAM in 1 & 2 Or just 1, or just 2 I had been trying for 1+3 or 2+4 to get dual ram slot 2 and 4 1 DVI-D 2 HDMI 3 USB Gen1 Type-A 4 Realtek® GbE LAN with cFosSpeed □ Memory: 8GB RAM or greater □ USB Ports: 3x USB ports plus 1x USB

ram slot 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

ramses revenge slot 3 2 x 10 GE SFP+ 6 Uses RSA-2048 certificate FORTIGATE 200F FORTIGATE 201F Interfaces and Modules GE RJ45 Ports 16 GE RJ45 Management HA 1 1  3 That board supports 4 DIMMS The manual also states a confusing; “Support for 1 Gb, 2 Gb, and 4 Gb memory technology