Should I set up a Fusion Drive in my Mac Pro?

This is my first post, so I apologize if this is in the wrong place.

I'm wondering if it's worth it for me to set up a Fusion Drive. Will I see a performance boost?

I've got an early 2009 Mac Pro running 10.10 the following specs:
20GB RAM
2 x 2.26 GHz Quad-Core Intel Xeon
ATI Radeon HD 4870 512 MB

My storage is set up as follows:
120 GB SSD – Used as my startup disk. Applications folder lives here
640 GB HD – Home folder lives here.
4 TB HD – I just installed this drive so right now it's got nothing on it.

I've been considering backing up all my data, setting up a Fusion Drive and then restoring. With the setup I'm running, will this make a difference in performance or am I better off just transferring my home folder to the 4 TB drive?

i don't think you can improve on your current setup.
changing over to the 4 TB should work.
HDD, SSD, and Fusion benchmarks for 27" iMac 2012