Should I put my page file on its own partition?

I have enough room on my OS hard disk to make a separate partition for the page file, but my power supply isn't enough to give it its own drive.

Is it better to put the Windows page file on its own partition, reducing fragmentation of the other partitions but increasing disk seek time (?), or to put it on the OS partition> (Or one on each)

If you are only going to be using one disk, place the OS and the swap partion on the first partition. You want all of the OS and swap files as close to ring 0 as possible as this will optimize the OS to be as fast as possible. The suggestion from JT to force it to a fixed size is absolutely a good idea. The OS starts getting very slow when it has to scale this on the fly.

I set the page / swap file to a fixed size so it isn't growing and potentially using other sectors on the hard drive. A separate disk is better than a separate partition, but the performance and maintenance gains are minimal for the effort.

How much memory do you have? If you have "enough", like, 2-4G usually, depending on your usage of the system, you shouldn't see any performance issues with this. If you don't have enough, add more. Its cheap!

The only time you will have a performance increase when partitioning is when the partitions are created on different drives. When partitioning a single disk it still uses the same head to read and therefore it will have no effect on performance, and it some cases even worsen it.

When using Windows either use a fixed swap file or just leave Windows to manage it. I rarely have to change the default settings for this.

The best way to speed up a machine is to add as much RAM as you can which can reduce the need to swap out often.