Probably drivers. It's going to take a bit to get drivers in the database for Windows 8. There's also some programs that won't run yet, but they will.
Just so happens that I also have Mint 12, it's on another HDD also. Mint 12 took longer than any prior version of Mint to get my graphic drivers right, almost a month. The first AMD/ATI drivers were really buggy. Finally, more acceptable drivers were available, and Mint 12 is fine now. Mint has a large following, more than Ubuntu now.
Zorin OS is going to climb the charts fast. Not only is it the fastest version of Linux that I run (Ubuntu 11.10, Mint 12 & Zorin OS 5.2), but when installed, you have the choice of the XP, Windows 7 or classic Gnome look. A lot of potential there.
Zorin OS - Home
Check it out. As far as your issue goes, probably drivers. I've tried to update the latest AMD Radeon drivers for my HP, it says "unsupported OS, XP, Vista & 7 is needed". Probably won't be long.
Cat