Invisible RAM

Anaksanamune · 14 Dec 2009 at 22:33

I have 6GB OCZ Platinum 1866 on an asus p6t deluxe and an i7 2.66.

About half the time I boot into windows, windows can only see 4 of the 6GB, however CPU-Z can always see the full 6GB.
Have tried rumming memtest86+ and Windows Memory Diagnosics and they turn up no errors.

Manually set to 1866, CL 9-9-9-28 @ 1.64V (databus).

Any suggestions as how to fix the dissapearing RAM would be helpful.

Anaksanamune · 14 Dec 2009 at 22:40

Windows 7 x64
QPI/DRAM Core is 1.25V (standard 1.2V) <- just for stability testing (see if it makes a difference).
DRAM BUS 1.64V (standard 1.5V) <- as manufacturure states

Anaksanamune · 14 Dec 2009 at 23:21

Since changing the QPI core to 1.25V from 1.2V it have been ok.
(Just rebooted 6 times, and memory has shown up correctly).
Not sure if this is the cure or I have just been lucky.
Don't even know what the QPI core voltage is, and as far as I was aware only the DRAM BUS needs to be upped for functionality at higher speeds.
Well I'll update this again after a few more reboots, and keep checking back to see if anyone has any suggestions.

Scratch this post...
Mobo reset the timings/speed etc while I wasn't looking...
Soon as I bumped up the speed windows repeatedly crashed.
Think its probbaly me, and not setting the timings up right.
I know that it needs to be 9-9-9-28, but then what? The mobo has more than 4 settings and I dont really know the values to put it for the rest.

Anaksanamune · 15 Dec 2009 at 00:59

I've checked out the max safe voltages before messing (although you would be suprised the number of guides that go over intel spec).
Just ran memtest again and it DID see all 6GB, so it must have been a glitch where it only saw 4GB - the same as windows and my whole problem.
Seems to be about a 1 in 5 change of 4GB showing up instead of the full 6GB (irrelevant of what timing/speed I use), tomorrow I will pull out the sticks and put them back in to make sure its nothing obvious like that. Will also try memory remapping.

EDIT: Discovery - All X58 boards have memory remapping on by default

Anaksanamune · 15 Dec 2009 at 21:01

I'm still at default speeds - 1066 and I am having the problem.
I don't mind running at a lower speed but slightly annoying if you have paid for 1866MHz RAM.
Taken it all out and pushed it back in, see if I keep having problems, if I do I'll need to RMA something I suppose.
Does anyone know of any RAM (6GB) that works 100% of the time with a P6T, or will I need to change Mobo?
Probably get the Gigabyte extreme if the problem doesn't fix itself, anyone know if this mobo will run happily?

Anaksanamune · 16 Dec 2009 at 15:12

It looks like a manufacturuing fault with some of the boards as far i can gather.
Looking around for solutions on other forums I can across this on Tom's Hardware.

I had the same problem as well. I purchased 7 of these mb's two had this problem, and I was using the exact same setup in each one. I talked with ASUS, they are aware of the problem.

Seems to just be luck of the draw as to if you get a working one or not.

Anaksanamune · 16 Dec 2009 at 18:24

Now I really don't know, what to suspect. I didn't think that the processor could be the cause only the ram and mobo. After memtesting the ram i think that it is fine, leaving only the mobo at fault. IF it could be the CPU, thats another thing I have to worry about / potentially RMA. Annoyingly I don't know anyone else with an X58 setup so I can't swap and see what the cause is. I have looked around a bit more and it seems evga and gigabyte boards also sometimes have this problem.