ATX motherboard too small for ATX case?

[bosoxx091]

Just tried putting my Biostar TA970 motherboard into the new Fractal Design Define C case and the standoffs on the right are about an inch off from the motherboard. The standoffs on the left and the soldered one in the middle fit perfectly. The rear I/O is also flush with the case.

Any ideas?

Pictures
http://imgur.com/a/1J8UE

 

[raisonjohn]

Standard (full-sized) ATX dimensions is 30.5cm (12") x 24.4cm (9.6"). Not all motherboard specified as "ATX"-sized are of this exact standard dimension. The Biostar TA970 is one example of this ATX-variant size: 30.5cm (12") x 22.5cm (8.86").

My motherboard for example is a Gigabyte H97 Gaming 3, though "ATX"-sized on specs, only measures 30.5cm (12") x 21.3cm (8.4"). It's mounted similar to your situation. Hate it when removing the 24-pin ATX power cable though as I feel the board is about to break when trying to pull the plug out the socket.