NP1

Ive built a new PC and this problem has been annoying me for the past week. Ive searched and posted in many forums/websites and no luck, so I thought i'd post in a PC dedicated forum. I will be as thorough as I possibly can when describing the problem:

I'm having trouble booting up Windows Vista Ultimate (x64) when there is 6GB of RAM installed. Windows was installed and boots up properly with 4GB of RAM installed (2x2GB sticks) however when adding an extra 2GB of RAM (2x1GB sticks), when Vista boots up (after the green bar screen) a BSOD is presented. I have noticed 2 different BSODs, one with the error code 0x0000001E (ecache.sys) and the other 0x000000D1.

Here is the RAM i'm using:
http://www.ocztechnology.com/products/memory/ocz_ddr2_pc2_6400_sli_ready_edition
(2x2GB sticks + 2x1GB sticks)

(For the record I understand that my Mboard supports Crossfire opposed to SLI (RAM was bought at an earlier date when I had an SLI Board))

The RAM are installed as follows:
The 2 2GB sticks are installed in the yellow slots (DIMM_A1 & DIMM_B1)
The 2 1GB sticks are installed in the black slots (DIMM_A2 & DIMM_B2)

My motherboard's manual claims that the board can support up to 8GB RAM.

I have installed all the latest updates for Vista x64 (incl SP1 and all KB patches and fixes) and installed the latest BIOS for my m'board.

Heres the full rig:

ASUS M3A32 MVP Deluxe - AMD 790FX Chipset
AMD Phenom x4 9950 Black Edition 2.6Ghz
TrueColor ATI RADEON HD 4850 1GB GDDR3
600W OCZ Stealth X Stream PSU
1TB Samsung SATA HDD 7200rpm + 250GB Western Digital PATA HDD 7200rpm
LiteON DVD RW
Windows Vista Ultimate x64 SP1 (with all updates installed)
Latest BIOS installed (v. 1203)

Now, ive have tested each stick of RAM individually using memtest 86 and no errors were reported.

Ive tried booting up Vista using different RAM combinations. It boots up fine with 4GB (2x2GB sticks) or 2GB (2x1GB sticks), its when I mix the two different types of RAM (1+2GB sticks) I run into trouble.

Once or twice I managed to boot vista with 3GB and 5GB of RAM but 9 times out of 10, a BSOD will appear upon boot of vista (even when trying to boot in safe mode)

If anyone can offer any suggestions (if anything involving BIOS tweaks, could they be detailed please) that would be great as i'm nearly tearing my hair out

Cheers

manic

More often than not, when all of the slots are filled seems there
are problems. I always prefer to use just 2 slots with a matched
pair running in dual mode. Rarely will you get dual mode with matched
ram in all slots. Just the slightest bit of a voltage difference can cause
a problem.
You may check bios and make sure that the voltage for ram is set
to 2.1volts, I believe that is the spec on your ram. You may try
bumping the voltage up a little, it may cure your problem. But I would
not bet on it, but its something you can try. I would not get to carried
away with bumping it up though be careful.
Unless your doing video editing, or something real ram intensive I would
settle on 4gigs in dual mode, more than enough for most people.