Re: Help me Decide on these Gigabyte Models.
What are your system components? especially your CPU.
Be Twin shouldn't be an issue. That is more of an OS compatibility than hardware compatibility.
The A55M board is an FM1 board for the Llano APUs.
Both of the 68 board are getting old. The current amd drivers cover 7xx series chipsets and newer.
The first one would be my recommendation. That is of course you current CPU is compatible.
ASRock Z68 Extreme3 Gen3 i7 2600K 8GB (2 x 4GB) G.Skill 1333 CL9 MSI HD 7750 Corsair TX850 80Plus
GigaByte A75-UD4H AMD A*-3870K 8GB (2X4GB) G.Skill 1866 CL8 On-Chip 6550D Antec EA-450 80Plus Platinum