8GB memory but only shows 3.5GB

  Pedro Campos 15:23 05 Jun 2009

I've just installed 4x2GB memory for a total of 8GB but my PC only shows 3.5GB.

Any ideas?

all memory is the same type, maanufacturer, etc, the motherboard is a Gygabite with 4 DDR2 memory slots and 2 DDR3 slots.

  Big Edd 15:35 05 Jun 2009

windows 64bit, linux or OSX?

Windows 32bit will just read a maximum of 4GB and usually shows just 3.5Gb

  ambra4 15:42 05 Jun 2009

The 32-bit version of Windows XP Professional can only use about 3.5GB of RAM.

Windows XP shows the amount of memory it can use

Windows Vista shows the amount of RAM installed.

If 4GB of memory is installed 3.5GB can be used by Windows XP the remaining half a gigabyte (0.5GB)

is not used by the system.

  Strawballs 18:00 05 Jun 2009

If you use a 64bit O/S then it will use all 8gig

  DieSse 00:06 06 Jun 2009

The cause is due to the memory addresses available. 32 bit windows can only handle up to 4GB worth of memory addresses. Of these anywhere from about .5 to .75GB worth of the topmost addresses are already reserved by various parts of the system hardware.

Depending on the specifications of each system, these addresses are reserved and so cannot be used by the Operating System.

The reason it's not the same for all systems is that it depends on the exact nature of the hardware in each system.

  Pedro Campos 10:03 06 Jun 2009

I am using windows vista 32bit... according to th epost in this 32bit editions can only take 4gb, but is there any setting i could change including BIOS?

  bremner 10:13 06 Jun 2009

No it is a 32bit limitation.

Wait till October and get Windows 7 64 bit and you will have all 8GB available for use.

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