NTFS compression and reported disk size

Hi,

I have a 500GB drive on a Windows Server 2008.

One of the folders on the drive contains around 450GB.

I want to use the NTFS compression to save up some disk space.

I did a test on a 5GB file.

I put it in a different folder on the drive and applied compression to that folder.

The file size stayed the same in the explorer window. I opened "My computer" and the drive free space stayed exactly the same.

Only when I checked the properties of the file I saw the Size On Disk value was 1.5GB.

Is this how it's suppose to be?