I just installed Windows 7 64 bit on a high spec computer which has 6GB of RAM installed. System under control panel says 6GB but only 3.25GB usable. How can I make the full amount usable? Many thanks for any advice.
From reading around it seems that it may be a bios setting to do with 'Remapping memory' that's in order. It could also be a limitation of your chipset, in that if it is 32bit then you will max out at 3.25 of usable RAM, hopefully this isn't the case.
Could you post the full spec of your PC please, especially your motherboard and RAM.
Can't find that motherboard anywhere, it must be a serial number of some sort. Download CPU-Z and run it. Once installed click the Mainboard tab and it should give you everything you need to know, MB, chipset etc etc. Like this -
Processor 1 ID = 0
Number of cores 4 (max 4)
Number of threads 4 (max 4)
Name Intel Core 2 Quad Q6600
Specification Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
Package (platform ID) Socket 775 LGA (0x4)
Extended CPUID 6.F
Core Stepping G0
Technology 65 nm
Core Speed 1595.9 MHz
Multiplier x FSB 6.0 x 266.0 MHz
Rated Bus speed 1063.9 MHz
Stock frequency 2400 MHz
Instructions sets MMX, SSE, SSE2, SSE3, SSSE3, EM64T
L1 Data cache 4 x 32 KBytes, 8-way set associative, 64-byte line size
L1 Instruction cache 4 x 32 KBytes, 8-way set associative, 64-byte line size
L2 cache 2 x 4096 KBytes, 16-way set associative, 64-byte line size
FID/VID Control yes
FID range 6.0x - 9.0x
Max VID 1.288 V
I would remove the 2gigs of slower RAM as they are dragging the other DIMMs down to their speed in order to operate properly, ie the 4gigs of PC-5300 are causing the other 4 gigs of PC-6400 to run at the same speed. 4gigs is plenty for W7 and you can always buy more of the same spec in the future if need be.
You could also try updating your bios since it is pretty old. At the minute it is using the Dixons bios but this can be overwritten with the Foxconn one. You can find what you need here.
that wouldn't be causing the problem. As long as both are compatible with the computer. One just performs a little better but still would give you the total memory amount.
Some machines will only give you a maximum of memory. For example in a laptop some max out at 2 GB of memory with two slots. Thus putting in 2 2 gb totaling four GB would only show 2gb in that computer.
I'm stumped as CPU-Z clearly recognises the 6GB installed (at the time). I know shared Video memory can eat into your RAM but not by this much. There should be a bios setting related to 'Shared VRAM' or similar which you can turn off. Your motherboard supports up to 8GB of RAM so there is no reason for this apparent limitation. Maybe someone with a bit more technical expertise can jump in?
I have had a very good look at the BIOS adjustments possible. There are no options which might improve this problem. I believe if I could flash the BIOS with a newer version it could sort out this problem but for whatever reason it seems to be locked and won't allow me.