4Gb on Acer Aspire 5715Z not working

[krs000a]

Hello,

My Acer Aspire 5715Z which came with 3Gb RAM (1 x 1Gb stick, and 1 x 2Gb stick).
I happened to have an extra 2Gb stick laying around, which I know for a fact works, because I have just recently tried it on another laptop.
So I wanted to put that in the Aspire laptop, to get 4Gb. Problem is that after doing so, it still says it got 3Gb and not 4Gb.
From what I gather, this model should be able to handle 4Gb RAM.
Why is this likely happening? Is there some setting I need to change?
Please explain easy, I am very bad when it comes to this tech stuff.
Many thanks in advance.

[downloads]

Do you have 64bit Windows or 32bit version?
32bit will not show more than 3GB anyway.

Check what BIOS shows.

[.NetRolller 3D]

Check in the BIOS for the actual RAM amount detected - that should show 4GB.

[krs000a]

32 bit version of Windows XP is what I got. Does that mean it only uses 3Gb, or only shows 3Gb? Will it still use all 4Gb, even though it only shows 3?

I have checked the BIOS, but I can't see the RAM mentioned anywhere at all.

[downloads]

BIOS has to show RAM but that's beside the point now.
Your Win XP 32bit is neither showing nor using 4GB.
Upgrading to a 64bit system would solve this issue.

[Greg]

Does CPU-Z show that you have the Intel 945 chipset? Even though it supports 64-bit processors, that chipset had a hard 4GB RAM limit (and you'll only get ~3GB). The Intel 965 chipset was the first to support 4GB+ of RAM. The reason you are seeing < 4GB is because, like all chipsets, the BIOS has to reserve address space to communicate with devices on the PC (search "Memory Mapped I/O" to learn more).