Assuming AE is on your system drive (which is preferable, IMO), you should always have your sources on another drive. I suppose rendering to a third internal drive would speed things up even more, but I’ve never tested that hypothesis.
I think the benchmark comp 2 winner is fastest because of the RAID. (array of disks)
Also, search the COW for “secret” or “schecret”, to find the secret prefs that can allow you to purge RAM during a render.
Steve