I have this problem with my Veriton M490G motherboard...
I had 4x4 gb ram in it, and bios didn't detect it correctly (16/7,96gb useable) for half a year, and one day it started to detect it. It was good for 1 months, now i had to take out the rams, because of cpu cooler changing, then i put them back and it didn't detect it again... rams are working alone, and i tried every variations to put them in. I tried reseting bios but it didn't help.
When i have:
any stick (1 or 2) in black: doesnt boot up
1 in blue: 4/2gb
2 in blue: 8/4gb
1 in blue 2 in black: 12/8gb
1 in black 2 in blue: 12/8gb
2 in black 2 in blue: 16/8gb
Anyone knows why does this happen?
Again, bios reset does not help, rams are connected correctly, rams are not faulty, msconfig max memory isnt checked, i have win10 64bit and once it was able to use all 16gb of these rams.