Recognising all 4gb ram?

[David (PassMark)]

If you have 4GB installed, I think it is unlikely that BurnInTest is reporting that you have over 4GB. What is it reporting?

Available RAM will be less than total RAM because some of it will be in use. This might be by the operating system, the disk cache, or other applications. This is a normal situation.

[lea.s]

I have 4 gig ram running Windows 7 Ultimate 64bit version.

In regards to the Memory Burnintest, it says total ram over 4gig but available is about half. Why would this be so?