Windows 7: 4gb ram 3 gb usable

Windows Experience Index

Understand and improve your computer's performance in Windows Vista

By Stephanie Krieger
When presenting at a user group meeting last week, someone asked me if a low Windows Experience Index (WEI) score of 1 or 2 means that he should not use Windows Vista on that computer. The answer is "not at all."
One of my favorite capabilities of Windows Vista is that it scales itself to fit your computer to help give you the best possible performance. For example, if your computer doesn't have the graphics capability to effectively display the new Windows Aerovisual effects, Windows Vista won't enable those effects on your computer.
In this article, I'll show you where to find your computer's WEI base score and subscores, as well as how to interpret them. I'll also show you how you can use these scores to help know what to look for when buying a new computer, upgrading your existing computer, or troubleshooting performance issues.
Finding your scores

Here's how to find your computer's WEI scores:

1. Open Performance Information and Tools by clicking the Start button , clicking Control Panel, clicking System and Maintenance, and then clicking Performance Information and Tools.
2. View the Windows Experience Index base score and subscores for your computer. If you have recently upgraded your hardware and want to find out if your score has changed, click Update my score. If you don't see subscores and a base score, click Score this computer.

This image shows the WEI scores for the computer I used to write this column:

i have the same problem.
I had 1x2GB 800mhz (kingmax) ddr2 , and then i bought one stick more
now i have 2x2gb of same memory, but my windows 7 x64 says it is only 3,0 of 4Gb

Note When the physical RAM that is installed on a computer equals the address space that is supported by the chipset, the total system memory that is available to the operating system is always less than the physical RAM that is installed. For example, consider a computer that has an Intel 975X chipset that supports 8 GB of address space. If you install 8 GB of RAM, the system memory that is available to the operating system will be reduced by the PCI configuration requirements. In this scenario, PCI configuration requirements reduce the memory that is available to the operating system by an amount that is between approximately 200 MB and approximately 1 GB. The reduction depends on the configuration.