12Gb suddenly shows as 8Gb!

[hunuok]

First my specs:

i7 920 @ 4.0GHz
3R Systems Prima Boss II 120mm CPU cooler
Asus Rampage 2 Extreme
12Gb GSkill DDR3 12800
Palit 4870X2 Revolution in CF
150Gb WD Raptor
300Gb WD VelociRaptor
1000Gb * 2 WD Caviar Black
1000W NC Top
Heroichi Cougar Big Tower
Windows 7 Ultimate RTM x64

Hi There,

I recently upgraded MB, RAM and CPU two months ago (new). After clean install of Win7 everything was working just great!

This afternoon, CPU meter in sidebar, system performance info (in control panel) and BIOS shows 8Gb! Funnily enough CPUz still shows 12Gb.

Removing 3 channels of memory and rebooting resulted in....NOTHING. No beeps, no BIOS posts-just a black screen with a "locked" message on the BIOS LED.

Trying 1 stick, 2 sticks, 3 sticks (in combo) resulted in the same result-NOTHING. 4 sticks worked but showed up as 4Gb, 5 sticks 6Gb ad 6 sticks 8Gb. Clearing CMOS faired the same results.

I have OCd the CPU to 4.0GHz WITHOUT altering voltages (all settings on auto)

What could be the problem? Bad sticks?

Thanks in advance!

 

[zigzag3143]

H

If you have a setting called max memory in BIOS, it should be unchecked

 

[Antman]

Check this setting in MSCONFIG

Start
Run
msconfig

.

 

[hunuok]

Hey there ZigZag

Thanx for the quick turnaround.

Unfortunately nothing in BIOS to that effect.

Have read about your suggestion in other forums

 

[usasma]

I presume that you have 6 sticks of 2gB each?
Have you tried a memory test with all sticks installed?
Have you tried resetting the BIOS to Fail Safe values?

 

[Antman]

If RAM sticks fail, you will have bigger problems than a disappearing total amount value.

Check msconfig for boot setting limitations. This is your first test, without exception.

Well, one exception - if someone physically removed the sticks.

 

[hunuok]

Hi there guys,

Just wanted to thank you for all your assistance.

Checked msconfig and checked BIOS. No luck.

I took out all memory and installed one by one in sequence.

2Gb each in slots 2, 4 then 6 (consecutive reboots).

Another 2Gb in slots 1, 3 (total 10Gb confirmed in system and CPUz).

However back to 8Gb after inserting last stick in slot 5!

I exchanged this with stick from slot 4 and system/CPUz recognized 6Gb!

I think one stick is bad which I will RMA tomorrow.

However I don't understand why this "bad" stick will subtract an extra 2Gb. ie, 5 good +1 bad stick registers as 8Gb usable, 4 good +1 bad stick registers as 6Gb.

Anyways, thanks again.