Santa gave me duff memory!!

[wellmad]

Merry Christmas all!!

Got some new RAM for crimbo this morning, corsair XMS2 6400 (2 x 1GB sticks), taking my system total up to 4GB.

I've had 2 sticks (2 x 1GB) of the same RAM in my machine for the past couple of months with timings set to 4-4-4-12 (as recommended on the sticks) and absolutely no issues.

Since adding the 2 new sticks this morning I've had some issues:

First of all, the BIOS recongnises 4GB and boots fine into windows. Windows however only recognises 3.25GB (not sure if this is actually a problem or whether its just a windows thing)

Secondly, my machine seems really unstable now; random blue screens a couple of times, programs (kasperski, win media player, apache server) bombing out with "instruction etc, etc, cannot be read", when these programs have never done this before. Surfing and running basic apps seems ok but anything more than that just crashes almost straight away

Does this sound like a bad bit of RAM or a system setting not quite configured correctly? I've tried setting the DRAM command rate to 2T and enabling DRAM static read control but this doesn't seem to have helped...Other than that there is no OC on this rig, RAM is running in 800MHz mode

system is as follows:

ASUS P5K deluxe wifi AP
Q6600 + thermaltake ultra 120 extreme with yate loon attached
4GB corsair XMS2 6400
80 GB hdd
500W PSU

any suggestions?

[george4]

Yeah I had the same exact problem when I got my last pair of ram (lots of BSOD). When I increased the voltage to the ram everything was fine, played crysis for a few hours without any problems

Check cosair's website for the voltage you need (probably 2.1) then go into your bios and fix it accordingly.

[wellmad]

sweet, thanks. the RAM does say 2.1v on the side. Had a look for DRAM voltage in the BIOS but couldn't see it with the other DRAM settings, is it called something else?

[george4]

Somewhere in the over clocking section?

"vDIMM: 16-step DRAM voltage control" maybe?

make sure you know the difference between overvoltage and total voltage you need. (For example on my mother board my ram base voltage was something like 1.8v and i needed to OVERvoltage it by +0.2v to get the ram stable) -- do NOT overvolt by 2.1 or youll blow everything up

[Agent]

Search for the 'not getting 4gb' thing, its covered almost daily - there is loads of posts on here about it

[Thorsson]

Windows 32-bit only recognises ~3.3Gb RAM, and any single program can only use 2Gb.

[wellmad]

Found the RAM voltage setting, it was labelled DRAM voltage but I couldn't see it until I set AI to manual....Things seem ok now but I'll keep an eye on it for the next few days....

Shame about XP only seing 3.25Gb, might have to go up to vista now...

Thanks for the help guys

[Splash]

Shame about XP only seing 3.25Gb, might have to go up to vista now...

*yawn* it's not an XP/Vista thing, it's a 32 bit OS thing. The only way to address the full amount is to migrate to a 64 bit OS (ie Vista 32 bit won't see any more memory for you, while 64 bit XP, Vista x64, any 64 bit *nix flavour will all make use of the full amount of RAM)

[BUFF]

Shame about XP only seing 3.25Gb, might have to go up to vista now...

32-bit Vista has the same problem - it's a limit of 32-bit OS.
Need to go 64-bit to get around it.

[peterb]

Worth running Memtest86+ as well to ensure that all the memory is operating correctly.

[Agent]

Not only is it a limit of the 32bit OS, but you need to make sure your motherboard can fully address the 4gig, not all can.

[amjedm]

Not only is it a limit of the 32bit OS, but you need to make sure your motherboard can fully address the 4gig, not all can.

I remember reading one of your previous posts about this issue - it's the reason I didn't upgrade to 4GB (that's why I've thanked you )