P55-UD3 Dual CHannel Memory not working

[EvilcB]

I am having a rather strange issue with a P55-UD3 R1.0 Mbd with 2x2Gb Generic pc1333 ram,  i570 CPU, 3Ware 9590SE Raid Card &  W7 x64 Ult

After recently reconfiguring the computer (added a RAID card) I noticed that the performance was pants

At first I assumed it needed more ram but then wondered why as it had worked OK with W7 before

Then I realised that windows 7 x64 was reporting 4Gb memory but only 2Gb available and on further investigation found that the ram is in single channel mode

I have tried all permutations of the 2x2Gb ram sticks, the only combo that works is 1 in slots 3 + 1 in each of 1 & 3, all others hang the machine

I have tried a matched pair of Kingston ram from another working pc - same result

With 4 sticks its shows 4Gb with 2Gb available ?

What I can't figure out is the BIOS screen shot which shows ram in slots 1 & 3 as per the manual BUT the next line says the enabled slot is 2??

Can anyone shed any light on this - have I missed the blindingly obvious ??

Any help gratefully received   

CliveB

[Dark Mantis]

Hi

No the problem is that you are trying to run our modules on the same settings as two. This doesn't work. You need to enter the settings manually and increase the voltage of the memory to compensate for the extra  loading on the memory controller.

Try increasing the memory voltage first. If it is supposed to run at 1.5v default try putting it up  to 1.55v, if it is 1.65v try 1.68v - 1.7v

[EvilcB]

Hi

Thanks for the prompt reply

Do you mean run "four" modules ?

I am only using 2 - in slots 1 & 3 the white ones

I am totally confused with the "Enabled Slot Mb" showing in column 2 as 2048?

I will try altering the memory voltage and report back

Cheers

Clive

[Dark Mantis]

If you are only running two modules do not increase the voltages.

I would suggest that you download and run Memtest86+ to check your RAM first.

Memtest86+        http://www.memtest.org/

Insert one stick of memory in slot 1 and run Memtest on it for at least 10 loops and if there are no errors then swap it over with the next one and continue untill you have checked all  modules.
If you have any errors the module is faulty.
If you have any faulty modules you will have to return the whole kit as they are matched.

Post back when you have done that with the results.

[EvilcB]

Hi Dark Mantis

I think my paranormal ability has extended to this computer 

I removed the ram from slot 3, upped the voltage to the next level and ran Memtest

Each stick ran with no errors for 12 & 18 loops respectively

I then added in the second stick and it booted as DUAL 

Just out of curiosity I then put the ram voltage back to normal and guess what it still runs in Dual Mode

Having been in and around computers since the time when Bill Gates was just called B, I never cease to be amazed at the illogicality of computer systems at times

That said - many thanks for your assistance

Regards

CliveB

[Dark Mantis]

You are very welcome and I am glad that it is all working alright now. Must have been that Ju-Ju I used on it