Not being able to use all 16GB of ram

tbean1

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Nov 4, 2013
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Hello, I understand that this has been posted many times, but I seriously can't seem to find a solution besides perhaps a fresh install of Windows, which is a last ditch effort. Okay, so the problem here is that I have four memory sticks (4gb each) installed and I have two different colored dimms on my mobo, blue and black. I noticed my computer running slow and saw that it was only using 4 gb out of 16gb so I tested all the sticks and one was a dud. I have two different pairs, both G Skill, but one Ares and one Ripjaws and both at 2133 (PC17000). I had the pairs running in the right dimm as in slot 1 and 3 and 2 and 4. Still can't get full 16gb, only 7.90 usable, though all the sticks are showing up in windows, CPU-Z, and even asus AI Suite II. I have updated my BIOS and tried the MSCONFIG fix, but nothing has worked. I Manually changed the speed to 2133 in BIOS and tried messing with the channels in BIOS as well, but nothing will work! Please, if anyone can help that would be great! I don't think I have a dimm slot that's dead since everything else is able to read them. Thanks in advance!

Specs:
ASUS MA99FX Pro R2.0 AM3+
AMD FX-8320 Vishera 8 Core 3.5gHz(4.0 Turbo)
Sapphire Radeon R9 270x 4GB 256 bit GDDR5 x2 (Crossfire)
Rosewill Bronze series 1,000watt PSU
G. Skill Ares series 8gb(4gbx2) 240 pin DDR3 2133 (PC 17000)
G.Skill Ripjaws X series 8gb (4gbx2) 240 pin DDR3 2133 (PC17000)
Genuine WIndows 7 Home Premium 64-bit

 
G. Skill Ares series 8gb(4gbx2) 240 pin DDR3 2133 (PC 17000)
G.Skill Ripjaws X series 8gb (4gbx2) 240 pin DDR3 2133 (PC17000)

Running multiple kits that have never been tested together carry no guarantee that they will work. You are free to do your own compatibility testing.

I can tell you that AMD FX CPUs support:
1600MHz memory speed with two DIMMs per channel.
1866MHz with one DIMM per channel.
Higher frequencies require an overclocked system.