Defragmentation VS Disc Clean up, Yeah I'm dense, but I know you guys can clarify ;) Options

[*Zatanna*]

I am in the process of doing a very long winded degraf right now. I do this periodically because when I start rubberbanding in the middle of playing the MMORPG I pay, it typically isn't so bad after I defrag.

So this morning I'm actually looking at what's going on during the defrag process. I noticed that the estimated disk usage before defragmentation is pretty much the same as the estimated disk usage after defragmentation. Also, the contiguous, fragmented and unmovable files look identical, as does the free (white) space. Forget that last sentence. Everything is still accurate.

I looked through some of the threads here and I noticed people talking about disc clean up versus defragmentation.

What really is the best maintenance method for good PC performance? And why? I would really like to have at least a bullet point type understanding of what's going on when the processes are run.