|You could test it to be sure.|
My opinion would be that if you in fact do need a swap, it would be better to have all drives with a swap file. Even slower it might be that the faster drive is running other things and a faster cache would be the second drive.
There would be little realized gain in either way would be my guess.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10