380DT case can only fit old BTX motherboard.  There is almost no modern motherboard that is BTX these days.  Almost all are either ATX, its variants, or proprietary.  BTX and ATX are not compatible.  In some perspective they are like mirror images. [IMAGE]   The only possible way to force fit an ATX motherboard in 380 case is extensive modification of case. In addition, DT uses proprietary psu of nonstandard form factor.  380 case front panel uses Dell proprietary ribbon cable which needs to be rewired for power switch etc.
Hey, new user here i have an old Dell Optiplex 380 Desktop form factor and I wanted to see if there was a compatible motherboard upgrade. I would love to be able to add a recent dell motherboard into it and if not I want to be able to to install a motherboard with recent CPU compatability (intel) thanks.
Compatible motherboard replacement for Dell Optiplex 380 DT