12GB installed only 7.93 GB available... Why?

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daniel_542

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Jun 10, 2017
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Im trying to upgrade my rig with an extra 4gb RAM.
Current setup:
Intel DQ57TM mobo with latest BIOS.
Core i5-760 (2.8ghz)
750W generic PSU
8gb (2x4gb) DDR3-12800 (running 1333mhz bus speed) unbranded RAM (micron technologies according to memtest86) and 4gb (2x2gb) DDR3-12800 crucial standard ram (all modules have fully matching timings for all speeds according to cpu-z)
Radeon HD5770 gpu (1gb)
2x120gb SSD (1 running win10x64 - normal day to day - and the other xp x86 - dev and some of my games)
I am trying to add the 2x2gb modules shown above to the 2x4gb already in the system.
When i run the 2x2gb i get 4gb useable with no issues, same for the 2x4gb showing as full 8gb in windows but if i try to run all 4 modules, i get it coming up as 12gb (5.93 useable) or 12gb (7.93 useable) depending on the order i put the modules into the ram slots. i have confirmed that memtest86 recognises all the ram and tests it without errors so i know all slots and modules are working. Any ideas peeps?

Additional. I cleaned and reseated cpu & cooler and restarted pc to find it shows 12gb (9.18gb useable) with modules as follows:
Channel a slots 1+2 4gb modules
Channel b slots 1+2 2gb modules

Memtest86+ v4.20 image available from most recent test (confusing bit is the 'ddr3-109 cas 4-9-9-24 when its running ddr3-1333 cas 9-9-9-24) but not sure how to upload it on mobile internet browser.

Links to pictures:
memtest86+ v4.20 results: https://drive.google.com/open?id=0B9KFYXNaGrBMTVdPX0t0c2hJenc
CPU-Z Memory tab: https://drive.google.com/open?id=0B9KFYXNaGrBMYm5Uek4xRzQ3R3M
CPU-Z SPD tab for 1 4GB module (the other is identical): https://drive.google.com/open?id=0B9KFYXNaGrBMcU05RTJXRlh3Zzg
CPU-Z tab for 1 2GB module (the other is identical): https://drive.google.com/open?id=0B9KFYXNaGrBMaVFWWm9oRDBZSkU
 
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daniel_542

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Jun 10, 2017
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Unfortunately, the bios only has voltage settings for the RAM - no clock speed options.
The other thing is that the RAM all has the same clock speed/timings for each different speeds which is why I am so confused.
Let alone the fact that having the ram arranged in different ways changes the amount of RAM that Windows reports usable
I originally thought RAM module fault but memtest86+ ruled that out as you can see (as did windows memory test)
I then moved to slot fault but then realised that usually a slot fault would cause RAM not to register at all rather than register but not be usable in windows
I then moved to CPU contact issue with pins so reseated and the result was an improvement of 1.25GB usable RAM. Could this be a CPU or socket fault on the motherboard perhaps?
 
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elbert

elbert

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Jan 11, 2005
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Its a stablity issue. You could try a small bit more voltage. It could also instablity in the drivers. Make sure you have the latest bios and all driver are updated. RAM company's are making 4 pack dual channel kits for this reason. You can also try to remap your RAM in bios if you have the function.
 
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daniel_542

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Jun 10, 2017
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Interesting theory. Drivers as in chipset drivers or more along lines of graphics/other drivers?
Remap RAM? Not sure what you mean by that. I have tried 1.6v instead of the 1.5v they normally run on, that didn't have any effect.
 
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shrapnel_indie

shrapnel_indie

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Jan 21, 2010
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Also... when you separate your RAM: do so evenly: put 1 slot 4GB and the second slot 2GB for each channel. This would look like this:

Slot 1: 4GB
Slot 2: 2GB
Slot 3: 4GB
Slot 4: 2GB

You should be able to reverse direction to so it would be:

Slot 1: 2GB
Slot 2: 4GB
Slot 3: 2GB
Slot 4: 4GB

 
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lin_6_

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Jun 13, 2017
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one might be a bad ram. try to put one ram stick at a time to know which one to replace.

and might be a compatibility problem, not all sticks are the same batch
 
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daniel_542

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Jun 10, 2017
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I have tried it both of these ways around and found that both ways display 12GB RAM but only 5.98GB available in Windows.
If I place it as the following, I get 3.98 usable:
Slot: Size:
1 2GB
2 2GB
3 4GB
4 4GB

If I do it this way around, I get (now) 9.18GB (used to show 7.89GB until I reseated the CPU) usable:
Slot: Size:
1 4GB
2 4GB
3 2GB
4 2GB

In response to Lin_6_:
All modules tested as fine both in singles and in pairs using memtest86+.
Also tested all 4 together and no errors detected.
I suspect it is possibly a memory controller glitch on the board or the board doesn't like this extra RAM for some reason.
The most confusing bit is the fact that it was 7.98GB usable on the 4/4/2/2 formation at first but after reseating the CPU, it started giving me 9.18 usable which is what leads me to controller issue as each module has tested OK with no errors.

Elbert:
I used to manually set my page file to 1.5 times to amount of RAM I have in the PC (an old Microsoft Recommendation I got years ago) but with having SSDs, I don't bother with page files at all now.
I will try setting up a page file for my OS and see if that changes anything.
Also, I literally only have voltage settings for RAM in my BIOS - no clock speed, timings or other settings for RAM at all (and believe me, I have looked everywhere to see if there is a later version - there isn't).

I am days away from changing the board for a better one with a better processor, I will see if I get better results from that and let you all know. I will also test it with 4 1GB modules to rule out compatibility issues with current RAM.
 
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daniel_542

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Jun 10, 2017
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I tested it with 4 matching modules of 1GB 10600 and it showed all 4GB usable in Windows so it is not motherboard/CPU issue.
It seems odd though as since I reseated everything last week, it has been showing 9.18GB usable in Windows (which I feel is a REALLY odd number but not half as odd as the 7.98 it was showing before reseating the RAM and CPU last week).
This would signify that Windows is finding 10GB useable and reserving the 0.82GB RAM for something or reserving 2.82GB for something.
Both 2 GB modules and both 4gb modules are full working order (confirmed by memtest86 when all 4 modules were installed and again when running the 2x2gb as a pair, the 2x4gb as a pair and each module individually).
I cant think of any reason why the system would be doing this.
Never mind, I have a different motherboard coming in a few days, which will run all 4 modules of my 12800 at their top speeds. I wont be tweaking voltages/timings/speed of RAM unless I run into the same issue again, in which case, I will force them to run at their rated speed, voltage and timing settings as per CPU-Z report to see if that sorts it.
Out of curiosity, could entering maintenance mode with all the RAM installed and resetting everything there resolve this do we think?
Wish me luck!!!
 
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daniel_542

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Jun 10, 2017
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I won the battle!
Upon performing a registry edit to clear the pagefile on shutdown and opening msconfig, going to boot tab, clicking "Advanced" and unticking the "MAX MEMORY" option, it instantly recognised all 12GB as usable in Windows.
Thank you all for your suggestions and assistance!
 
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