Full ram not being used, 16GB only 8 usable

[Holay]

Hello, I have 4 Gskill 4Gb ram sticks, but only 8 gb are being used, i tried booting with a single stick to try all the ports, it boots correctly on ports DDR3_A1 and DDR3_A2 but when i try booting the single ram stick on ports DDR3_B1 and DDR3_B2 it wont boot and the debug codes on the board will show code 50 or 54, when i try to boot with slots DDR3_A2 and DDR3_B2 with ram sticks installed simultaneosly it does boot, and the BIOS detects both rams sticks (although it says single channel mode) but windows says 8BG(3.99 usable)

I already checked that the timing and frequency parameters are correct.

also removed the CPU to check for bent pins, and made sure the water cooling wasnt too tight

Do i have faulty ports? or am i doing something wrong.

Thanks for the help in advance

My motherboard is a Fatal1ty 990FX professional edition

i have 64 bit windows 10 pro

 

[Kieran10]

Hey,
Is all the sticks the same?
This might be the boards problem there might be a faulty slot.
Sometimes if the ram came in 2's they have to be in pairs, This is normally colour coordinated. e.g if the slots are labelled 1 2 3 4 the 2 sticks would be in either 1 and 3 or 2 and 4.

 

[Holay]

Hey,
Is all the sticks the same?
This might be the boards problem there might be a faulty slot.
Sometimes if the ram came in 2's they have to be in pairs, This is normally colour coordinated. e.g if the slots are labelled 1 2 3 4 the 2 sticks would be in either 1 and 3 or 2 and 4.

Yes, all the sticks are Gskill Ripjaw 4GB sticks (F3-12800CL9D-8GBXL) , they are occupying all 4 slots.

Also, thanks for your quick answer

 

[Kieran10]

Hey,
Is all the sticks the same?
This might be the boards problem there might be a faulty slot.
Sometimes if the ram came in 2's they have to be in pairs, This is normally colour coordinated. e.g if the slots are labelled 1 2 3 4 the 2 sticks would be in either 1 and 3 or 2 and 4.

Yes, all the sticks are Gskill Ripjaw 4GB sticks (F3-12800CL9D-8GBXL) , they are occupying all 4 slots.

Also, thanks for your quick answer

I found a previous post for you, they had the same problem. http://www.tomshardware.co.uk/answers/id-3176679/16gb-ram-installed-usable.html Hope this helps

Kieran