Yes, I tried it, it does speed up the load.
As for saving the file, if you have SD loaded, it leaves a tray app (SD Launcher Tray or something like that.) That tray app uses the DLL, so while it is in use, it can be changed/saved/deleted. You have to close the tray app first.
Anyway, like I said, it does speed up the load somewhat, but I decided to splurge on my carPC and treat it to a new drive, a
120 gB SATA II Solid State Drive Hopefully that should speed things up even more...