Available Memory issue with Windows 7

[Monstermunch]

I'm running an Asus P6X58D-E Motherboard and originally installed windows with only 6gb RAM (3x 2gb).

I managed to get a recent upgrade 3x sticks of 4gb and removed the old but windows will only recognise 8gb.

Even on boot it only seems to see 8gb but I have updated the bios and any motherboard drivers and nothing seems to see the 12gb except through CPUID which reads correctly.

Can anyone help?

 

[PiKe]

Put the RAM in the black slots only. You can't run dual channel with 3 sticks.

 

[Monstermunch]

What?

That makes no sense it's tri-channel memory and motherboard!

 

[bremen1874]

Which slots are you using? The manual appears to want the blue slots populating first.

Have you tried each stick on it's own to check that they're all good?

 

[PiKe]

Right well I didn't know it was tri-channel, which slots are you using?

A1, B1 and C1 need to be populated first, blue slots as the poster above states.

 

[Orcvader]

Didn't LGA1366 boards have an issue where if the cooler is on too tight it caused the system to only use two RAM sticks? Maybe try reseating the CPU and see if that helps.

 

[bremen1874]

If the OP has pulled three 2GB sticks and put three 4GB sticks in their place you'd expect it to work (assuming everything is compatible).

Information about the actual specs of the old and new memory would be helpful.

Also were the memory settings adjusted to allow for the new memory?

 

[Monstermunch]

Old 3x 2gb was Patriot Viper

New 3x 4gb is Corsair Vengeance 1600mhz Cas9

All settings in bios are left as standard, all on auto. When I try and set it all manually it won't boot but having said that i'm pretty useless when it comes to bios settings!

 

[PiKe]

What happens if you populate all the slots with he new and old ram?

 

[Monstermunch]

You can't mix sizes with the tri-channel stuff

 

[PiKe]

Is all the vengeance exactly the same model?

 

[Monstermunch]

Is all the vengeance exactly the same model?

Yes, it's a proper tri-channel kit. Bought as a 3x 4gb kit

 

[bledd]

Does each stick work one at a time in the 3 slots?

 

[Monstermunch]

Does each stick work one at a time in the 3 slots?

Tri channel boards do not boot with a single stick

 

[bledd]

My apologies, I've never used a tri channel board

 

[bremen1874]

Tri channel boards do not boot with a single stick

Why would be believe that? Single-channel, dual-channel, triple-channel, are all fine.

To quote the manual (section 2.4.1):

Recommended memory configurations
One DIMM:
You may install one memory module in slot A1, B1 or C1 as a single-channel operation.

 

[Monstermunch]

Why would be believe that? Single-channel, dual-channel, triple-channel, are all fine.

To quote the manual (section 2.4.1):

I read many places that you couldn't....

Now tried that and even tried swapping them all round, also tried 2 sticks etc. as well. No difference...

Everything is working fine and showing in CPUID but not bios or windows, even msconfig says only 8gb available

 

[Destination]

What OS are you using?

-edit
specifically which version of windows 7.

 

[jpaul]

a google shows many comments of this variety

I sure hope your new CPU cures your issue, but the missing memory problem is extremely common with i7-900 series CPUs in triple channel memory mode. Probably the most common issue people have with this platform. It comes and goes, I've seen hardware monitoring tools show different amounts for memory at the same time, and even on different tabs of the same too

(well over 95% of this type of failure are a single bent CPU socket pin)

 

[Monstermunch]

What OS are you using?

-edit
specifically which version of windows 7.

Pro 64, I know about the 8gb limitation of the home edition ones