said by jmn1207:
Depending on the motherboard/chipset you have, maybe the Intel Smart Response Technology would be an ideal solution?
On my Asus P8Z77, I can use a SSD up to 64GB that acts as a cache. From what I have read, the performance is greatly improved when booting and loading new programs.
This would allow you to keep your OS and storage on the larger MHDDs, even in a RAID configuration, while utilizing the much faster access time of the SSD for the applications that get used more frequently.
I'm still in research mode about this, but it might be something to consider if it proves to work as advertised. A fast 64GB SSD is relatively inexpensive.
That's Intel Smart Response Technology. However, IIRC, ASUS also has a proprietary SSD caching option on their new motherboards that will make use of SSD units larger then 64GB in capacity. If you want to know more check your manual or the ASUS support page for your board.
I know my ASUS P9X79 Deluxe motherboard has it which is my newest board but that's X79 not Z77 based.