Depends on what you are using it for. If the SSD is already formatted and in use, then no. My understanding with RST is that you can take any fast storage and tell it to act as cache for another slower drive. Basically turns any drive into a hybrid drive when you mix an SSD with a standard hard drive.
Samsung also offers their Magician software? Might have the name wrong, but it lets you use system ram as a cache for Samsung SSDs.
Presumably the same could be done with RST using a RAM drive.
Basically comes down to how much performance you are expecting out of a given drive and if it is meeting your needs. Not really much you can do about drive reads from source hard drives, this would mostly be about writes and actual workloads.
If you are just using a HDD as bulk storage for games or media, then it probably won't make a huge difference.