ASUS M2N-SLI Deluxe RAM Issue

[physei]

I've had this MB for over a year with 2Gb Corsair XMS2 RAM with no problems. I bought 2 more sticks of RAM, exact same RAM. MB fails to boot when all 4 sticks are installed. I've tried the new RAM by itself and it works fine, so that's not the problem. The manual says all RAM must be 2 paired sticks and that's what I have. Anyone has any idea what is the issue here? TY.
Info:
Motherboard: ASUS M2N-SLI Deluxe
RAM: Corsair XMS2 CM2X1024-6400C4DHX 1Gb per stick, 800Mhz, 4-4-4-12 2.10V ver5.1

 

[roonj]

You could use cpu-z to examine each pair to determine if the spec's on the chips are in fact matching. Latency and voltage.
If all matches and you have set voltage correctly try bumping to 2.2v as 4 chips require more voltage with quite a few systems.

 

[physei]

OK, I've checked with cpuz and both pairs are exactly the same, running at 2.1V
Now I need to figure out how to increase voltage. Thanks.

 

[physei]

Found the BIOS setting for RAM voltage. Increased voltage several times up to 2.3v and didn't work. However, I found out what's going on. Apparently this MoBo will only take up to 3Gb RAM when using Windows XP. That's it!
I removed one of the sticks, leaving 3x1Gb and it works. This doesn't make sense, since the manual insists RAM must be installed in pairs. Go figure...

 

[VPCTech]

Hi Physei. I have the M2N-E SLI and I think the 'must be installed in pairs' statement may only be to take advantage of Dual-Channel....?? not positive, tho.

 

[physei]

Yes, and the Corsair XMS2 6400 is Dual channel. I thought it's not supposed to work in singles. So now I have in fact, a pair and a half installed and working fine. The MoBo manual even include a chart on how to pair the memories. There's no indication at all about installing one pair and half of another.