There are some limitation with Fat32 that may preclude usage. ie max file size is 1 byte less than 4 gigs. So if you intend to place a 4gig, or larger file size - OPPS, no workee.
Other lmitations: http://support.microsoft.com/kb/314463
Interms of speed: a Ramdrive is approx 10 times faster than a SSD. NOTE it will slow down start-up and shutdown times as the Ramdisk contents will be read into memory form hard drive (SSD or HDD) and writen to the hard drive on shutdown.
Ramdrive I use: http://memory.dataram.com/products-and-services/software/ramdisk/
Free for Creating a Ramdrive upto 4 gigs, $19 for creating larger than 4 gig drive (I got it for $15)