What is a mSATA SSD Drive?

I wouldn't grab a mSATA drive for that motherboard, I have the Z77-D3H, so one version back from what you have And in the manual it states that

Transcend 256GB mSATA Internal SSD - mSATA SSD 230S Solid State Drive - with DDR3 DRAM Cache, ReadWrite - up to 550400 MBs

joker times xmas slot SSD Hard Disk MSATA SATA M2

slot lv casino A version of the SATA interface for solid state drives in mobile devices mSATA uses the same plug and socket as Mini PCI Express