[Need Help] AMD Motherboard Ram Issues

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, with being stuck in single-channel and windows only detecting 4gb (and again, the uefi and CPU-Z detecting all 8gb). 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 of 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), and GT 520 as Dedicated PhsyX

Storage: Various hard drives, Windows 7 installed on a 1tb Seagate HDD

Sound Card: Asus Xonar Essence ST (PCI)

PSU: Coolmax 900w ZU-900B (80+ Bronze)

Case: NZXT Phantom

Sounds like it shouldn't be either RAM or motherboard at this point. One technical possibility would be a bent or otherwise damaged CPU pin, or a CPU itself damaged for instance from excessive voltage at some point.

well first of all make sure you installed the ram correctly in dual channel mode. so that means you need to use the right slot combination. slot 1/3 or 2/4.

you could try a bios update.

Also there is a memory remapping option is enabled. in the bios, you probably can try that first. it can have diffrent names on diffrent motherboards, so check the manual for that ☺


That is what I was starting to think, because I have discovered that if I put both RAM sticks in the first 2 DIMM slots (A1 and B1), the the memory runs at their proper speeds (1600mhz at cas 7), and 7138mb is free for Windows to use. This is rather peculiar because only A1 and B1 slots on my old motherboard would work too, so I'm starting to think it may be a problem with the memory controller on the CPU, and getting a new CPU will fix the issue.

I can't think of anything else, so maybe that will be the only solution. Thank you for the suggestion!

Yes, I have the ram installed on A2 and B2, as the manual suggests. I have also tested all of the other slots, and they all of the same results.

I am updated to the latest bios (2.50), and that didn't fix anything.

My motherboard's uefi unfortunately doesn't have that feature, so there's nothing I can do for that.

Thank you for trying to help.

Try droping the ram down to 1333mhz in the bios (the AMD Phenom II x4 965 BE officialy only supports ddr2-ddr3 upto 1333mhz some chips can handle 1600mhz with out problems and some cant)

well did you also check your msconfig if there is a maximum memory usage is set to 4GB? this could also be the issue.

go to Start> run> Msconfig > boot up computer tab > advanced option tab > disable the max memory support.


This did increase the memory amount for windows to 8gb, so thank you for the suggestion.

This doesn't fix the issue of it only running in single-channel, but now I can at least edit and render videos without worrying about running out of memory.

Thank you. :)

ah thats great haha. ☺ That max memory setting just came up my mind, and thought that could maybe your issue..and i was right ☺

Well can you post a printscreen from cpu-Z memory tab? i wanne know the numbers you have on there. because maybe you get the numbers wrong. i think the number you see there will be 667mhz, in that case you fine, because its dual channel mode., you have to equals that number x2. meaning 1333mhz.

Here you see my ram tab i have 2x8GB 1600mhz.

grtz Angel ☺

Here's the screencap:


It is at 800mhz, so 1600mhz total. I know the Phenom II x4 965 is only supposed to go up to 1333, but I'm having no stability issues running at 1600mhz. Although, it is still in single channel mode... and nothing I do will fix that.

well its wiered, but if its working fine, and you dont have stability issues then i think you will be fine. i personaly think that the memory controller in the cpu, causing this issue then. i think the cpu has a problem to handle 1600mhz in dual channel mode. Maybe if you clock them back to 1333 or even 1066mhz.. but thats probably not worth a try..

Your mobo and ram seems to be fine. so probably your memory controller in the cpu causing it. probably wenn you upgrade your cpu someday, it will be fine.

if you have a friend with an FX cpu, you could test it.