Problem with 4GB of RAM

Yes gives 2.00GB and also Task Manager

Go to msconfig/ Boot tab, click on the advanced button halfway down on the left and check that the maximum ram is unchecked (on the right top of the screen.) Not sure why but some are and some aren't. This limits what your os see's/ utilises.

Checked and it is unchecked - Thanks

Thanks Reap3R I wasn't aware of that option. I usually don't mess with msconfig unless I am checking my system.

No worries Clifford_cooley, you can also select the amount of cores your cpu has in the same area, meant to speed this up a little or so I have read.

andyrpsmith, Did you do a fresh install or an upgrade when you first installed? Also, is 7 your only OS or are you using dual boot with 7 installed on the second half of the HDD (secondary partition)? Not sure if it would really make a difference but I read somewhere that 7 likes being at the start of the HDD, I can’t remember where it was but it was awhile ago I think, can anyone confirm?

Windows was a fresh install on a new HD.

What is strange is that if I replace 2 x 1GB modules in slots 3 and 4 with 2 x 512GB windows sees a total of 2.5GB

Have a close look at the contacts in this slot. Maybe one is not quite 'true' and only making a spasmodic contact!

Yeah I would be getting an eraser and rubbing it over all of your sticks contact points. Then check there is nothing in the slots on the MB. A can of compressed air is perfect for this. With the 2x1GB + 2x512MB you should see and have usable 3GB not 2.5GB. Have you got Memory Remapping enabled or disabled in the BIOS? This will directly affect the amount of seen ram in the OS. If I disable it with 6GB installed I only see 5.2GB in the OS as I have a GTX275 picture card.

If you have got Memory Remapping set on auto, set it to Enabled. If it is then I would suggest that DIMM slot 4 is faulty on your MB which would explain why CPU-z showed it as empty before. This would also explain your BSOD you are getting. Might be time to upgrade…

Reap3R normally I might agree with a faulty slot 4. If it wasn't for the fact that he had 4x512 installed without problems. And when he switched the modules around in slots 1&2 there are no problems either. This would suggest that the memory is good and the slots do read memory.

The only thing I can think of would be the memory remapping that Reap3R suggest.

I think the no mem in slot 4 was an error with CPU-z as it has done this a couple of times and then reads the correct values. CPU-z agrees with the BIOS detection and gives the correct timings etc. My son has the same mother board and is using XP so I am going to try the mem in his and see what it reads.

Thanks for all the suggestions by the way. One good thing is that the BSOD has been stopped by changing the Flexibility option to enabled in the BIOS.