Does having a full hard drive slow down computer?

On my vostro 1500 with vista home premuim my hard is pretty much full 115gb of 120gb are being used. My question is would having less on the hard drive increase computer performance? And if so, how much of a difference would there be?

 

The only bad thing about running out of hard drive space is the lack of a page file that the OS needs. As long as you have enough free space for the OS to use as a necessary page file, then it doesn't matter if you only have 1mb free or the full 120gb free.

 

Yes, performance does decrease as you fill up your hard drive. The reason for this is that hard drives have the highest transfer rates on the outer area of the platter. As you move progressively toward the inner area, the transfer rate decreases.

 

While that's very true, it's not the full story. That's because the hard drive does not save the first files in the quickest area, and then progresses towards the slower areas as you fill it up. It is random.

So you can have 1gb of used hard drive, and that 1gb could be located in the spot of the hard drive that has the worst performance. Thus, even if your hard drive is empty, you can still have as bad performance as if it was completely full and having to access stuff on the edges.

 

I think some of the "smarter" file systems like ReiserFS try to store data near the faster region when possible, but I'm not sure. In any case, that is a way to improve performance. (However, it would not improve performance with Flash - if anything, it can cause early failure by concentrating writes in one area.)
I suppose you could partition the disk to put the frequently used programs in the fastest area, the rarely used/small programs in the slowest area, and the home directory in the middle, but it's tricky to size the partitions. And the shuffling back and forth between partitions can eliminate performance gains.
If you have plenty of RAM, the swap partition/file would not be used very much in the first place. Many years ago, I actually set up a Mandrake test system with 384MB of RAM and no swap at all. It worked fine, although I did not multitask anywhere as much back then. Now, I do put swap partitions on my systems for those rare moments when RAM is not enough.

EDIT: You could use LVM for dynamic partitioning.

 

It is a good idea to leave at least 1GB free space in your C drive at all time for the following reasons:

1. Most programs need temporary space in your hard drive in order to function. This temporary space will be cleared once you stop using the program but it needs that space while it's running.

2. Your web browser also needs temporary internet files to speed up browsing. If you don't have any fee space left for the web browser to save temporary internet files, you may notice a slow down when using your web browser.

3. If your hard drive is already fragmented, you will not be able to defrag it if your hard drive is almost full.