AMD Motherboard Only Runs RAM In Single-Channel & Windows Only Detects 4GB

[Cirofost]

Hello, I'm having issues with my RAM in my new motherboard (ASrock 990FX Extreme4), with it only running in single-channel, and Windows only detecting half of what's there.

First of all, I had a 2 x 4gb 1333mhz G.Skill memory kit (F3-10666CL9D-8GBSR) with a Biostar A870U3 motherboard. It would not run in dual-channel, because only the A1 and B1 slots worked, however Windows did recognize all 8gb in single-channel.

Now I got a new ASrock 990FX Extreme4, and the G.Skill ram not only would not run in single channel, but windows only detected 4gb (While the uefi and CPU-Z detects all 8gb). I thought it was a problem the motherboard, so I ordered an RMA and got a replacement, but the replacement has the exact same issues.

So then I thought it was an issue with the ram, so I bought a new Corsair 2 x 4gb 1600mhz ram kit (CMZ8GX3M2X1600C7R), and I am still having the exact same issues. On top of that, despite the motherboard detecting the XMP profile to run in the rated speeds and latencies, it will only run the memory at 1333mhz with a CAS latency of 9, when it should run at 1600mhz with a CAS latency of 7. Even if I manually change it, it will not run higher than 1333mh at cas 9.

I have tested all DIMM slots on the motherboard and they all work properly. I have cleared the cmos many times, and I have tweaked with the RAM settings in the uefi but nothing will fix the issues. Also the motherboard runs ram in unganged mode by default, but if I try to switch it to "Auto", then the computer will not boot, but Ganged mode does work with one RAM chip in, not both. I am not running a 32-bit version of windows, which I know has a max amount of ram to 4gb.

The only solution I can think of is sending back the replacement and just getting a different motherboard entirely (I was thinking of the Asus M5A99FX PRO R2.0).

I will list my entire computer specs below. Any insight on this issue would be greatly appreciated.
Thank you all very much.

OS: Windows 7 64-bit
CPU: AMD Phenom II x4 965 BE
Motherboard: ASrock 990FX Extreme4
RAM: Corsair 2x4gb 1600Mhz (CMZ8GX3M2X1600C7R)
GPU: Nvidia GeForce GTS 450 1GB (Using two monitors, both 1366x768)
Storage: Various hard drives, Windows 7 installed on a 1tb Seagate HDD
PSU: Coolmax 900w ZU-900B (80+ Bronze)
Case: NZXT Phantom

 

[vicstead]

I know nothing about these boards. I would suggest that you contact Corsair Customer Support, I have found them very helpful in the past.

 

[Tradesman1]

Might try and see if the MOBO has DOCP (I think it does) or EOCP, if so try enabling that and select 1600 else w/ the 965 can try manually:

1. Set DRAM Frequency to DDR3-1600

2. Set CPU-NB Frequency to 2400MHz (DDR3-1600 / 2 = 800MHz, then x 3) CPU-NB Frequency should always be 3X DRAM bus frequency

3. Set HT Link Frequency to 2400MHz

4. Set timings to tCL 9 - tRCD 9 - tRP 9 - tRAS 24, or whatever your memory is rated for.

5. Set DRAM Voltage to 1.50V, or whatever your memory is rated for.

6. Most CPUs will need a CPU-NB Voltage boost of +0.10V, so if your default is 1.10V, set it to 1.20V.