"Seperate partition" don't cut it, as kalpik points out, you need seperate disks. Preferably a small, seperate, fast hdd (raid0 and scsi may not be necessary, but they help) dedicated for virtual memory. And if you have multiple hdds, you can distribute your swap file on different partitions on each disk (I don't know if does a raid0 or just a jbod internally).
And don't let windows auto-manage it for you. Rather take the maximum that windows sets and set it as the minimum too. This will eliminate the need for page file defragmentation later. And the maximum set by the windows (1.5x the RAM size, I believe) is not a mandatory rule.
But don't disable page file too, even if you have 2GB of RAM. If you have >=2GB of RAM, then you probably are using heavy apps that may reserve large blocks of memory. You'd better spare some hdd space than receive an "out of memory" error in that case.
Finally, if your page file use is too high, don't keep increasing the size. Try to buy some more RAM.
Also, format the partition to ntfs with a large block size. If it's a raid0, first format it with a large stripe size and then format it ntfs.