I've taken a bunch of RAMDisk solutions from this 3year old article, and tried them on my own machine (Ivy Bridge i7/16GB RAM).
Using Crystal Disk Mark with 50MiB files on 1GB RAMDisk images, formatted with FAT32. Here are my results (yours may vary):
Note: 14 day trial
Note: Free!
Note: 1GB free
Note: Free (open source)
For interest sake: Primo Ramdisk on my Haswell i7 32GB RAM