Only 16gb usable out of 32 gb

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impesio

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Aug 14, 2017
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510
I tried to read some of the other question regarding this problem but I couldn't resolve the problem.
SO: windows 10 pro x64.

MOBO: MAXIMUS VII FORMULA
CPU: Intel i74790K CPU
RAM: 4x8GB Corsair Vengeance 2600 Mhz. Since I noticed I run out of memory in the last period I bought an extra 2x(GB Corsair identical to my previous 2x8gb pack.

The problem is that windows recognizes them but he said that i can use 16 GB of them at maximum. I tried switch ram, remove some of them, switch placed but no matter what configuration I use (even if I use an asimettrical configuration) the problem won't solve.

I looked in Windows task manager and it says that 16 GB of ram are used in hardware.
I tried updating bios, but nothing is resolved.
I read about going in msconfig and toggle check in "max memory" but the box was already unchecked.

What should I do now?
 
Solution
Barty1884
There are slight variances in chips used, voltage requirements etc.

Just because a 2x8GB kit has the same serial number, does not mean the same identical chips were used in it's manufacturing processes.

As with CPUs/GPUs, RAM dies are also of various 'binned' quality, and their voltage requirements (and usually their max speed) is arrived at as a result.
BUT, that doesn't guarantee any two different kits, no matter how similar, will work correctly 100% of the time.

The difference between 2 (supposedly) identical kits could be as minimal as very slight voltage increase, or loosening of timings etc.

"Kits" sold together (2x8GB, 4x8GB etc) have been tested from the factory, and confirmed to 'play nice' with each other. While it is...
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Barty1884

Barty1884

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With "mixing & matching" RAM, even theoretically identical "kits", there can be issues (that's why RAM is sold in "kits" to begin with - tested to work together).

You may be able to add a slight voltage boost to the memory to have them "play nice", especially trying to enable XMP.

Just to be 100% certain here, you are using Windows 10 as per your tag, correct?
Just a note that if this were Windows 7 Home, the cap is 16GB. Windows 8 or greater has a 128GB cap (for x64, still 4GB for x86)
 
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R

Rookie_MIB

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Jul 27, 2013
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First thing I would try to do is reset the RAM settings in bios to bone-stock default (as in 1333mhz, stock timings). 2600 is 'oc mode' and for a set of RAM to work together properly at the higher frequencies they HAVE to be matched and sold as a single kit. Plus, while a pair of ram modules might work together, putting an additional pair in there can cause problems. See the issues they have with Ryzen - when that first came out the modules were incredibly picky.
 
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I

impesio

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Aug 14, 2017
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510


I wrote it in the second line. Sometimes I found combination where with only 16 GB of ramb only 8 where used but moving one of the banks in another slot that returned to 16/16. But even this way, when I added the other two bank it was 16/32.

I tried enable XMP but, since I'm not used with BIOS, I ended up in a serie of error (23, 55, a2) and I returned to auto option.

And furthermore, the RAMs are identhical and the problem was presentes as soon as I installed them, when the pair were still correct.
 
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impesio

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Aug 14, 2017
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510


I said 2600 Mhz but in reality al the RaMs run at 1333 Mhz becouse I couldn't manage to improve it. Obviously I reset all option of the BIOS.

I have this problem since the first time I installed the ram bank. Obviously before trying play statistic game they were paired in the right way and the problem still existed.
 
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I

impesio

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Aug 14, 2017
8
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510
I removed alle the rams just right now. I tried to understand what were the pair. I opened the MOBO manual and followed the reccomanded instrucions on pairing but the problem persists.

Both pair of RAMs are (CMY16GX3M2A2400C11A) and the difference lyes in version. One is 3.1 and the other is 5.1

I tried going into BIOS and activatend XMP without overclock and It did non gave me any problem in starting but the PC still says 16/32 Gb ram used.
 
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I

impesio

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Aug 14, 2017
8
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510


What does it mean "mixed Rams doesen't work" they have the exact numerical code. All four of them and that is CMY16GX3M2A2400C11A. I tried repairing them (the etiquette was printed in different ways) and still doesn't work. Am I missing something from "mixed Rams doesen't work"? What should I do?
 
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rgd1101

rgd1101

Don't
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return the "new" 2x8, sell the existing 2x8
get a 4x8 kit.
 
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I

impesio

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Aug 14, 2017
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510


Thank you. Just for curiosity... Why this happens?
 
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Barty1884

Barty1884

Retired Moderator
Apr 16, 2015
22,250
1,350
108,740
There are slight variances in chips used, voltage requirements etc.

Just because a 2x8GB kit has the same serial number, does not mean the same identical chips were used in it's manufacturing processes.

As with CPUs/GPUs, RAM dies are also of various 'binned' quality, and their voltage requirements (and usually their max speed) is arrived at as a result.
BUT, that doesn't guarantee any two different kits, no matter how similar, will work correctly 100% of the time.

The difference between 2 (supposedly) identical kits could be as minimal as very slight voltage increase, or loosening of timings etc.

"Kits" sold together (2x8GB, 4x8GB etc) have been tested from the factory, and confirmed to 'play nice' with each other. While it is possible to have two individually purchased kits just 'work', it's not guaranteed. It's also not something the manufacturer will assist with either, as your ram is 'different'.
 
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Solution
I

impesio

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Aug 14, 2017
8
0
510


Since I am here, can you explain me why when I try to force the ram to run at 2.4Ghz with XMP my MOBO gives me errore code 23?
 
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