Dual channel memory issues 16gb installed 8gb detected.

Satheon · Jun 27, 2013

Hello

My computer properties shows that 16gb is installed but only 8gb is usable and my system bios only shows 8gb installed.

I have also checked with CPU-Z and that shows 16gb installed, although it says that the memory is running in single channel mode rather than dual channel.

I am using 2 sets of Corsair vengeance 8gb RAM which has 2 sticks of 4gb each.

I am using Windows 7 Home Premium so there shouldn't be an issue with the maximum memory allowed for my version of Windows.

I have tried reseating the RAM and testing it one by one and the computer still boots fine, I did find that trying to boot with a single stick of RAM in either the 3rd or 4th slots did not work and the monitor did not light up.

Booting with a single stick of ram in either the 1st or 2nd slot works fine.

Any help would be appreciated as this has been bothering me since I built this computer in 2011.

Motherboard - http://uk.asus.com/Motherboards/AMD_AM3Plus/M5A97_PRO/
RAM - http://www.corsair.com/vengeance-8gb-dual-channel-ddr3-memory-kit-cmz8gx3m2a1600c8.html

Tradesman1 · Jun 27, 2013

Might check - Start, enter MSCONFIG in the search box, hit enter, in the window that opens, select the boot tab, then advanced, then see if MAX Memory is checked and uncheck it

Satheon · Jun 27, 2013

Tradesman1 :

I looked at that previously and its already unchecked.

Tradesman1 · Jun 27, 2013

Do you have the latest BIOS?

Satheon · Jun 27, 2013

Tradesman1 :

Yeah, I updated to the latest bios (version 1604) a few months ago.

Tradesman1 · Jun 27, 2013

Pull and reinstall the sticks, if currently in slots 1-2 might try in 2-4, might also try each individually and see if any problem with each by itself, may be a bad stick or a bad slot

Satheon · Jun 28, 2013

Tradesman1 :

I said in my first post that I'm using 2 sets of dual channel memory, each set contains 2 sticks of 4gb for a total of 16gb.

I have already reseated each stick and tried them 1 by 1, I also tried using just a single stick RAM in each slot to see if it would boot, first I tried installing a stick into slot 1, waited for it to boot then powered it off again, I did this for all 4 slots using just a single stick each time.

Slots 1 & 2 booted up fine but slots 3 & 4 did not boot at all, could this just be a setting somewhere that is stopping these 2 slots from being used?

The pc boots up fine with all 4 sticks installed but the problem of only 8gb of that being seen by windows and bios is still there.

Tradesman1 · Jun 28, 2013

If both slots that are problematic are same channel, i.e. 1-3 or 2-4 than may be a MC (memory controller) problem in the CPU, installation of the CPU (may loosen the heatsink and make it snug, not too tight) or could be a bad trace to the slots, or just bad slots

Satheon · Jun 28, 2013

1 & 3 are dual channel and 2 & 4 are too, that would mean its the 2nd slot for each dual channel set that is not working as intended.

Tradesman1 · Jun 28, 2013

Sort of sounds like mobo, but might try with the CPU heat sink, too tight can do weird things

Satheon · Jun 28, 2013

Due to it being an AMD CPU the heatsink is quite tight by default, the laches that hold the heatsink in the socket take a bit of effort to lock in securely.

It's not really possible to loosen it without making it unstable.

CPU is an AMD Phenom ii x4 955 @ 3.2ghz.

Tradesman1 · Jun 28, 2013

Have you checked for bent/broken pins on the CPU

Satheon · Jun 29, 2013

Tradesman1 :

I did have some trouble when building this computer a few years ago, I needed to remove the CPU from it's socket and in the process of taking the heatsink off, the CPU came out with it. This caused some of the pins to bend but I managed to straighten them.

I didn't think this would cause any major problems but I guess I was wrong.

If I were to replace the CPU would I get a noticeable change in performance due to the RAM working in dual channel mode?

Tradesman1 · Jun 29, 2013

If that's the problem, quite possibly could see a good size jump

Satheon · Jun 29, 2013

So just to be certain, there are no hidden options anywhere that could be disabling these 2 slots or dual channel mode?

I generally use this computer for gaming, would the increase in performance be noticeable for this process?

Tradesman1 · Jun 29, 2013

Still could be the mobo is just bad, but I would lean towards the CPU - hard to tell without hands on...i.e. in a shop could easily try a different CPU, or try your CPU w/ a different mobo

Satheon · Jun 29, 2013

If the performance difference is not that much then I might just stay with what I have and wait till I can afford to upgrade the CPU and motherboard. The CPU is starting to show its age in recent games so I think its almost time for an upgrade anyway.

Thanks for your assistance with this issue.

Tradesman1 · Jun 29, 2013

Wish we could have done more

Dual channel memory issues 16gb installed 8gb detected.

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