Replacing motherboard in optiplex 790/990

[Amaides]

Hi was just wondering if I could put a new motherboard in an optiplex 790/990 case. Would the mounting holes match up? Will the front panel connects match? Will the standard I/O shield fit in the cast? And what form factor should the motherboard be? Thanks!

 

[Bootrec]

I was about to write "no", but I wanted to make sure and grabbed a 790 out of my pile, and compared board dimensions and screw hole placements with the ATX specifications. Standard micro ATX boards are 244mmx244mm (9.6"x9.6"). The actual Dell board size is 203mmx263mm. The hole placement seem to match but then I can't be sure... the imperial to metric conversion and screwing up with me. Even if holes would somewhat match, the connectors for front panels definitively don't match; Dell uses proprietary connectors. You could venture into pulling out each wires from Dell's connectors and try to fish them in a standard connector, but I wouldn't know where to begin. The power connectors seem standard; 24pin and 4pin for CPU. Newer motherboards need a 8pin CPU power connection though (thinking the 990 is newer and might have the 8pin? Not sure). And lastly, the rear I/O window seems the same size, but it is not removable on the Dell chassis. You would have to cut through the steel.

 

[Amaides]

I was about to write "no", but I wanted to make sure and grabbed a 790 out of my pile, and compared board dimensions and screw hole placements with the ATX specifications. Standard micro ATX boards are 244mmx244mm (9.6"x9.6"). The actual Dell board size is 203mmx263mm. The hole placement seem to match but then I can't be sure... the imperial to metric conversion and screwing up with me. Even if holes would somewhat match, the connectors for front panels definitively don't match; Dell uses proprietary connectors. You could venture into pulling out each wires from Dell's connectors and try to fish them in a standard connector, but I wouldn't know where to begin. The power connectors seem standard; 24pin and 4pin for CPU. Newer motherboards need a 8pin CPU power connection though (thinking the 990 is newer and might have the 8pin? Not sure). And lastly, the rear I/O window seems the same size, but it is not removable on the Dell chassis. You would have to cut through the steel.

Thank you very much!