motherboard and case confusion

[caddyshack]

This is the first time building my first PC, I assmed that when a motherboard said atx form that it was a specific size and therefore would fit in to a case that accepts atx motherboards. My case came yesterday and I noticed that on the box it said max system board size 10x12. There are was never a mention of the max board size on new egg or the manufacturers site. The motherboard I want to get is 12x9 , this may seem like a dumb question but will it fit? I just don't understand why there are different size boards and there was no mention of a max board size capacity when I bought the case. I already had to return 3 things to newegg due to them being incompatible which was not my fault as it was not shown on new egg. I have tried to find a board to fit inside the case but to no avail. Any help with finding a board to fit in the case would be appreciated sorry for the long rant. The case is a deep cool tessarect and here is the mobo:

 

[GhislainG]

If it can fit a 12x10 motherbaord, then it will fit a 12x9 motherboard.

 

[synphul]

Most atx layouts have the motherboard lengthwise up and down. Taller than they are wide if stood up as it would be in a case looking at it straight on. Hard to tell without knowing the exact case. Like GhislainG said, if it supports 10x12, it should support 12x9 (the measurements could have been reversed, L & W).

 

[caddyshack]

OK thank you I am new at this. Next time I build a computer I will have to do more research on what I'm buying. I did not realize what I was getting in to when building my own pc. I have another question about psu's. What would be sufficient power for this build if I wanted to delve in to overclocking? Fx 6300 black edition, sapphire r9 280x, Asus m5a97 mobo, corsair vengeance 8gb 1600 ram, DVD rw drive, 1tb Seagate barracuda, and two case fans ? I have tried many different wattage estimators and they all have me answers ranging from 600-900 watts

 

[GhislainG]

A quality 550-600 watts PSU is enough.

 

[hwc1954]

Motherboards are pretty standard sizes these days. It should fit without any problems.