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Windows 7: 4GB Memory Unusable


04 Jul 2010   #1

Windows 7 Ultimate x64
 
 
4GB Memory Unusable

I finally got my new I7 980X CPU today so went to fire up my newly built PC but the POST screen only shows 4GB of memory. Re-seated the chips and still only 4GB. Memtest86+ V4 shows all 4 sticks of 2GB Corsair ram as present but only says 4GB as well.

Installed Windows 7 and it says 8GB installed. 4GB usable. This is the 64bit version so I am expecting to get the whole 8GB.

Anyone know who or what is holding the other 4GB to ransom and what do I have to pay to get it released?


My System SpecsSystem Spec
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04 Jul 2010   #2

Windows 7 Home Premium 32-Bit
 
 

Quote   Quote: Originally Posted by veldthui View Post
I finally got my new I7 980X CPU today so went to fire up my newly built PC but the POST screen only shows 4GB of memory. Re-seated the chips and still only 4GB. Memtest86+ V4 shows all 4 sticks of 2GB Corsair ram as present but only says 4GB as well.

Installed Windows 7 and it says 8GB installed. 4GB usable. This is the 64bit version so I am expecting to get the whole 8GB.

Anyone know who or what is holding the other 4GB to ransom and what do I have to pay to get it released?
IS the bios set to read 8gb ram?
My System SpecsSystem Spec
04 Jul 2010   #3

 
 

When the machine POSTS, does it show 4GB or 8GB? How much does it show in the BIOS?

Is it only happening since you replaced the CPU, or is it an entirely new machine totally built from scratch (including the RAM)?

There are several causes for this:

► RAM Timings to aggressive/tight (loosen the timings)
► Insufficient DRAM volts
► Poorly Seated CPU - improper pad/pin contact (re-seat it)
► Cooler too tight/ loose (cooler tension affects the pin/pad contact)
► Bad RAM modules
► Bad dimm slots
My System SpecsSystem Spec
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04 Jul 2010   #4

Windows 7 Ultimate x64
 
 

It is brand spanking new all round. POST shows 4GB. Have everything in the BIOS set to auto so timings should be pretty loose as I wanted to get it working before starting to tweak. The memory chips speeds are rated much higher than what they are actually running at (needed room to move).

Will try the CPU cooler. It was a dog to get on. Artic Cooler Pro and has two screws to tighten but you cant see them to put them in.
My System SpecsSystem Spec
04 Jul 2010   #5

Win 8 Release candidate 8400
 
 

Quote   Quote: Originally Posted by veldthui View Post
It is brand spanking new all round. POST shows 4GB. Have everything in the BIOS set to auto so timings should be pretty loose as I wanted to get it working before starting to tweak. The memory chips speeds are rated much higher than what they are actually running at (needed room to move).

Will try the CPU cooler. It was a dog to get on. Artic Cooler Pro and has two screws to tighten but you cant see them to put them in.

Check what max memory is set to in msconfig. (type msconfig in search). It should be unchecked.
My System SpecsSystem Spec
04 Jul 2010   #6

 
 

Quote   Quote: Originally Posted by veldthui View Post
POST shows 4GB. Have everything in the BIOS set to auto so timings should be pretty loose

Will try the CPU cooler. It was a dog to get on. Artic Cooler Pro and has two screws to tighten but you cant see them to put them in.
Yep, auto should be loose enough.

Although to double check you could set it to 9-9-9-24 or so @ 1066mhz with a TN of 2 to completely rule out timings

The fact that POST/BIOS shows only 4GB points to it being hardware. So there will nothing that can be done within from Windows itself.

I had a similar issue with this current build initially - I kept losing 2GB while POSTing and it turned out to be the CPU cooler tension. Once adjusted properly, it's been solid.

But I also managed to replicate the memory loss at post when tweaking my RAM. So yeah, there are several possible causes.
My System SpecsSystem Spec
04 Jul 2010   #7

Windows 7 Ult, Windows 8.1 Pro,
 
 

Besides trying Smarteyeballs good advice I would try the following procedure.

I would try shutting down the machine, unplug power from PSU and drain power by pushing start button. Remove half the Ram from every other slot. Restart the machine check to make sure all 4GB are picked up by Windows. Shut down again and repeat procedure of draining power, install one stick at a time repeating the same procedure each time and see if Windows picks them up each time you restart.
My System SpecsSystem Spec
04 Jul 2010   #8

Windows 7 Ultimate x64
 
 

I tried the cooler. When I loosened it off it only POSTed 2GB. When I tighten it back up regardless of how much it still only POST's 4GB. What is strange is that MemTest86 and Windows both show 8GB there. Windows 8GB installed, 4Usable. MemTest86 shows all 4 stcks of 2GB but again only tests 4GB of it.

Cant see any options in the BIOS that would disable the mem. The timings are 7-7-7-24 @ 2020mhz. Well within the specs of them.
My System SpecsSystem Spec
04 Jul 2010   #9

Windows 7 Pro X64 SP1
 
 

Quote   Quote: Originally Posted by veldthui View Post
I tried the cooler. When I loosened it off it only POSTed 2GB. When I tighten it back up regardless of how much it still only POST's 4GB. What is strange is that MemTest86 and Windows both show 8GB there. Windows 8GB installed, 4Usable. MemTest86 shows all 4 stcks of 2GB but again only tests 4GB of it.

Cant see any options in the BIOS that would disable the mem. The timings are 7-7-7-24 @ 2020mhz. Well within the specs of them.
Here's a semi-random suggestion:

Your system must support triple channel memory. What happens when you use only 3 DIMMs, in a triple channel configuration?
My System SpecsSystem Spec
04 Jul 2010   #10

Windows 7 Ultimate x64
 
 

The system is a DDR3 system with 6 DIMM slots. It says to stick memory into slots 2,1,3,5 for 4 modules. I stuck one moduke in 1 and it would not POST. 2 modules in 1 & 3 and it posted with 2GB. 3 modules in 1,3,5 and it posted with 4GB. I then tried slots 4 and 5 with more modules and got the 8GB. However it will work with anything in slots 1 & 2. It is detected but it wont POST the size and it cant be used.

I may have a faulty motherboard. I have had one BSOD as well with the 8GB but I was playing around with the timings and it may not like the memory in the other slots. The manual says 1 first but it is out of action.
My System SpecsSystem Spec
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 4GB Memory Unusable




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