RAM upgrade causing issues - GA-P35C-DS3R and Corsair XMS2 DDR2 800MHz

So first off I have a Gigabyte GA-P35C-DS3R motherboard, with 4gb of Corsair (2 x 2gb) XMS2 DDR2 800MHz RAM

Needed at least 8, so checked the motherboard specs and it allows up to 8gb for DDR2. Brought new RAM, (brought 16gb (8x2gb, this is for 2 machines, then was going to move the current 4gb to another machine)).

Anyways long story short I cant get the machine working with anything but 4gb. Either it wont even POST, or it does POST but I get past GRUB and it tells me 'uncompression error, system halted', or it will just infinitely (left it for 45 minutes) sit and blink with the cursor top left (and in recovery mode it gets up to 'freeing initrd memory').

As I brought RAM for another machine I have lots spare to try, and its all matched. I suspect one set is dud as thats the one when it wont even post. I have tried various sets in various slots, and it all comes down to it works with 4gb (any set, except the suspected dud), but I cant get it working with 8gb (however it does POST)

Any ideas? Pulling my hair out! RAM usually either works or it doesnt, none of this POST but cant boot the OS

Have you tried upping the north bridge voltage, also known as mch on some boards. With all slots filled this often needs a bump in voltage to cope with the strain of all dimm slots being filled.

thanks for the tip, tried upping it 0.2 volts but no joy

also theres 1 splot free, even though thats a ddr3 slot, so its not technically fully loaded

I am stuck for what else to try. It boots fine with 4gb, but 8gb it POSTS but wont actually boot up an OS. Am using ubuntu, and also wont boot off of an Ubuntu live cd. Haven't tried windows yet, worth doing?

Also ran memtest for a bit yesterday and there were no errors, tbh I didnt run it for long but could leave it going overnight

I would try +0.3V on the MCH and see if you get any luck

Also, what are specs of the memory?

Have you tried loosening the timing slightly?

ok will give it a try. am waiting until i have a bunch of things to try so i can do them all in one go, messing about inside the pc and making it not work is killing my productivity

anymore ideas?

Slackening timings and upping the NB a fraction more is about it - although you could lower the frequency for testing purposes if the BN tweak and slacker timings didn't work.

You could consider upping the DRAM voltage (over spec) slightly but i would leave that as a last resort (it technically voids the warranty).

I've heard rumours that it will work with 8gb of DDR3....... I'm very temted to try it out when I get paid next week. If I do I'll let you know how it goes!

Bump...hmmm 4 x 2GB should be fine in this board.

I'm currently running 2 x 2GB but looking to upgrade to 8GB for BF3, so would be interested to hear if the OP resolved his issues...

Failing that I'll have to look at 2 x 4GB of DDR3, as hinted at by beninfluence.

I ran my one with 2x2GB and 2x1GB sticks.
Both OCZ but different XMP timing ones. One set was a Reaper 800MHz, while the other was a 800MHz ATI Optimized set. Reapers had 5-5-5-15 timings and the other had 5-6-6-18. But I ran them both at 5-5-5-15 @ 800MHz no problem. Had to increase the MCH volts by +0.1V.

Better try memtest86 with a bootable CD/usb

Screw it, just ordered 8GB (2x4GB) Corsair DDR3 XMS3, PC3-10600 (1333), Non-ECC Unbuffered, CAS 9-9-9-24, 1.50V for £28.79 delivered. Will let you know if it works .

Robbie G said:

Screw it, just ordered 8GB (2x4GB) Corsair DDR3 XMS3, PC3-10600 (1333), Non-ECC Unbuffered, CAS 9-9-9-24, 1.50V for £28.79 delivered. Will let you know if it works .

Click to expand...

I'm using 8GB (2x4GB) DDR3 1333 in my GA-P35C-DS3R (rev 1.1) and it works without any adjusting.
Here's an account of someone using 16GB (4x4GB) DDR2 in a GA-P35-DS3L three years ago: http://www.soundsonline-forums.com/showthread.php?t=17728

I'm looking to put 16GB in mine to see what happens.

have you bumped the vdimm voltage? i remember running at +0.3 when i had 8GB in my p35-ds3l. i also bumped up the mch by +0.1

The RAM I'm using is G.SKILL F3-10666CL9D-8GBRL and it just worked when I installed it.

I have made no adjustments to vDIMM or MCH because I know next to nothing about any of those types of settings.
I have some electrical engineering education so I could probably pick things up fairly quickly. I have never applied what I do know to the art/science of tweaking computer systems.
Can you recommend any material on the subject?