HELP: 16GB 2(2x4GB) Installed, 8 usable (Windows 7)

[cardsixteen]

System Specs (links for reference, I didn't buy refurbished/open box)
Gigabyte GA-970-Gaming (rev 1.1)
AMD Phenom II X6 1090T
Mushkin Enhanced (996988S) (4x4GB) DDR3L 1600
GeForce GTX960 4GB
Windows 7 Pro x64


Problem:
-Bios recognizes 16gb of ram installed, Windows recognizes 16.0GB installed (7.98 GB usable)

-Frequent bluescreen when running games or CAD software like AutoCAD or RevIt

-Had to set ram timing and voltage manually, BIOS did not do it automatically


Attempted Solutions:
-Bios updated to latest version

-No ram cap in msconfig

-Reset cmos using jumper and removing battery

-If I only install 2 modules (2x4GB... 8GB) Windows only recognized 4GB usable

-No overclocking

-Memtest 86 ... 4 passes, Zero errors

If you have any ideas please let me know, I've read a bunch of threads with similar problems but none of their solutions have worked for me. Gigabyte's list of compatible ram is outdated, many of them aren't even sold anymore as far as I can tell.


UPDATE
Replaced CPU with and AMD FX-8350. Windows recognizes all 16GB of ram but I'm still getting frequent bluescreens.

 

[spdragoo]

Possibly the RAM isn't compatible with the board. It's not technically on the list (https://www.gigabyte.com/Motherboard/GA-970-Gaming-rev-10#support-doc), which could be why you had to set the voltage manually (DDR3L running at lower voltages than DDR3).

As for the "RAM available", that's just indicating how much isn't being used by Windows. The more RAM you have, the more RAM Windows will take.

 

[Calvin7]

Model 996988S is not a (4x4GB) kit. Memory is guaranteed in the form sold, i.e. a (2 x 4GB) kit. Other combinations have no guarantee to be compatible together.

Such combinations are done on a "Do It Yourself" compatibility testing basis as the old and new memory has never been tested together by anyone else but you.

Your OPEN BOX CPU may have a damaged memory controller.
CPU Introduction date April 27, 2010
Official AMD support is for 1333MHz memory. Higher frequencies have been known to damage the memory controller.

 

[cardsixteen]

Model 996988S is not a (4x4GB) kit. Memory is guaranteed in the form sold, i.e. a (2 x 4GB) kit. Other combinations have no guarantee to be compatible together.

Such combinations are done on a "Do It Yourself" compatibility testing basis as the old and new memory has never been tested together by anyone else but you.

Your OPEN BOX CPU may have a damaged memory controller.
CPU Introduction date April 27, 2010
Official AMD support is for 1333MHz memory. Higher frequencies have been known to damage the memory controller.

Replaced CPU with an FX-8350 that supports higher frequency memory. Windows now uses all 16GB but I'm getting blusecreen still. Current memory configuration worked fine for years - trying to figure out what changed.

Going back to one 2x4 kit results in the same system instability.

 

[cardsixteen]

Possibly the RAM isn't compatible with the board. It's not technically on the list (https://www.gigabyte.com/Motherboard/GA-970-Gaming-rev-10#support-doc), which could be why you had to set the voltage manually (DDR3L running at lower voltages than DDR3).

As for the "RAM available", that's just indicating how much isn't being used by Windows. The more RAM you have, the more RAM Windows will take.

It's not on the list, but that list is so dated that all the ram listed either isn't available or is obsolete.

 

[bananatiger]

Try putting the AMD Phenom II X6 1090T back. Go to your bios and into the north bridge configuration. Click the dedicated video memory and change it from automatic to off. Try testing your pc if its stable. (This solves the 8gb usable problem, and yes I read that update part in the description)

 

[cardsixteen]

Try putting the AMD Phenom II X6 1090T back. Go to your bios and into the north bridge configuration. Click the dedicated video memory and change it from automatic to off. Try testing your pc if its stable. (This solves the 8gb usable problem, and yes I read that update part in the description)

Doesn't look like there's a way to disable or specify display adapter on either cpu.

 

[cardsixteen]

Figured it out, two things were corrected:

1. The "usable memory" problem was solved by upgrading my cpu to one rated for 1600mhz.

2. The bluescreen errror - checked the windows crash log which showed a video adapter problem. Tried uninstalling, updating divers, no luck. On a hunch I removed the riser cable going from the GPU to the motherboard, and plugged it in directly - voila, no more blusecreen. I don't know why it works, but it does.