P55-UD3 - will not enable dual channel mode

[xav2075]

(This is the same post as in 'Intel Motherboards with Intel Processors' main forum section.  I did'nt realise this subforum existed.  Mods can delete that previous thread if you like)

I am unable to get my motherboard to enable both 2GB memory sticks in dual channel mode to give me 4GB in total.  It just gives me 2GB in single mode.  What is weird that the M.I.T status BIOS screen can recognise that there are 2 x 2GB memory sticks plugged in.  But it will not enable the 2nd memory stick.  At default CPU speed the problem is still there.  I have reset the BIOS many times when trying to get this to work.

This screen shot shows what i mean:-


As per the manual i have plugged the memory in slots '3_1' and '3_3' for dual channel mode:-


.

In single channel mode the BIOS can recognise and enable both 2GB memory sticks:-

Memory plugged into slots '3_2' and '3_1' for single channel mode:-


Memory is Corsair CMX4GX3M2A1600C9 DDR3 dual channel kit. Using XMP memory profile and 9-9-9-24 manufacturer settings. I am using F6 Bios.  Did try F7 BIOS at stock cpu speeds but again dual channel mode did'nt work.  Put it back to F6 bios as F7 would not let me set CPU voltage to 1.39 or 1.4 voltage, weird that.

Any ideas folks?

[decrypter]

Hmm strange , i had same mobo n ram as you and i had unstable rig , so i switched to g skill and never looked back , if you have cpu-z run it and check your ram , it says in there dual/single channel and whats running etc

[xav2075]

Tried dual channel mode for the zillionth time (with all BIOS defaults and XMP memory profile enabled) but still not working.  Windows 7 also can 'see' 4GB but only utillise 2GB.  CPU-Z says 'Dual' but the BIOS POST screen does not.

[decrypter]

On the SPD tab on cpu-z  you can check both slots    1+ 3 check both are posting in dual , also why do you have xmp enabled only use this if you are doing  a huge overclock , says that you have i5 @ 2.72 ?     disable xmp n try again aswell      should resolve it

[frayedknot]

I have the exact same issue; same board and pretty much same memory... your memory is CMX4GX3M2A1600C9 and mine is CMX4GX3M2A1600C8.

I'm sure a BIOS update will fix.

Was going to try increasing the voltage to the ram to see if that makes a difference.. had that kind of issue in the past with DDR2.

[cortez]

Same problem here (CMX4GX3M2A1600C8 and P55A-UD3). Memory can't run in dual channel, only in single channel. If I put them in dual channel the system becomes unstable and gives errors in Memtest86+. I hope Gigabyte will do something soon...

[maros]

Hi all,

My solution is for this issue,that the mobo can't handle dual chanel memory :

The first thing we have to know that it's not memory problem it's not a mobo problem,and the cpu is responsible for some memory settings.
In my case I had core I5-760 cpu  ,tried to put memories to the white slots ,each memory is 
2Gb so total memory has to be 4Gb,but only showed 2Gb in the Bios .I replaced the cpu to I5-750,and with this cpu all datas were correct.
After I put back the original cpu to the mobo,and YES it showed the correct values.
So,I think it was just my fault,pleace the cpu correctly to the socket,and everything should be fine !

I hope it will work for anyone !!

[Dark Mantis]

Hi all,

My solution is for this issue,that the mobo can't handle dual chanel memory :

The first thing we have to know that it's not memory problem it's not a mobo problem,and the cpu is responsible for some memory settings.
In my case I had core I5-760 cpu  ,tried to put memories to the white slots ,each memory is 
2Gb so total memory has to be 4Gb,but only showed 2Gb in the Bios .I replaced the cpu to I5-750,and with this cpu all datas were correct.
After I put back the original cpu to the mobo,and YES it showed the correct values.
So,I think it was just my fault,pleace the cpu correctly to the socket,and everything should be fine !

I hope it will work for anyone !!

Badly fitted CPUs are a common fault and can result in bent CPU socket pins and missing memory amongst other things. As you rightly pointed out it makes no difference what processor you have in there if it is not carefully installed.