I once got a case that contained an Acorp 6BX81motherboard. (Image: http://www.motherboard.cz/mb/acorp/6bx81.jpg
) The case has no brand name on it, the only identifying mark I saw was, "2A495-01 Rev. B."
I'm also working on building a PC using an MSI 790FX-GD70 motherboard. I decided to try using the unidentified case for the motherboard. All of the landing holes in the case lined up with those on the mobo. Additionally, the I/O ports fit in after I removed the 6BX81's custom fit plate from the case. However, after I finished screwing the motherboard in, I found that PCI cards would not fit. The PCI slots on the motherboard were positioned about one mm too close to the back "wall." This surprised me. The whole point of the form factors like ATX being created in the first place was for parts to be interchangeable, am I correct?
Anyway, when I inserted the 6bX81 motherboard into a Gateway Series 1000 case, the PCI cards fit perfectly, implying the MSI motherboard may be the problem. Perhaps the screw holes were punched in off-center. (I hope that's not the case, because I'm pretty sure the warranty already expired.) I already tried screwing an existing E-machines mini-ATX mobo made in 2004 into the unidentified full-size ATX case, and a PCI card fit, but it was really tight, implying the case is the source of the problem.
I can't put the MSI mobo into a different case to see how it fits because the Gateway Series 1000 case is the only other full-size tower ATX case I have, and it has I/O holes for the motherboard that came with it cut directly into the case, and thus wouldn't fit my mobo.
I'm worried about buying a case for the MSI mobo because I'm worried it won't fit. What do you think is the cause of the physical incompatibility, and what should I do?