Hi, I have two drives and one for storage an the other is my operating system. I know compressing drives can take up cpu power but it can also make your hard drive hold nearly twice as much. Right now I don't have much on my hard drives an I have my storage drive compressed an my operating drive uncompressed. I was thinking later when it gets bigger I can compress it. Is it possible to compress files that are already downloaded on the hard drive? Also, do you guys think its worth it to compress drives or is it worth it to slow down the cpu on my p4 processor and 512mb ram computer. thanks for any help