Why don't I see 4GB?
This is often reported and answered, but as 3 people asked about this today, I thought I'd blog it (sorry if you've seen this elsewhere a few times)
Symptom
If a computer has 4 gigabytes (GB) of random-access memory (RAM) installed, the system memory that is reported in the System Information dialog box in Windows Vista is less than you expect. For example, the System Information dialog box may report 3,120 megabytes (MB) of system memory on a computer that has 4 GB of memory installed (4,096 MB).
Basically this is a chipset restriction not a Vista one, for more detailed information we have a support article here:
https://support.microsoft.com/kb/929605/en-us
Clive
Technorati tags: Windows Vista