Mt are not sff. Dell has used 4 sizes for optiplex for years. Usff, sff, dt, and mt are also all standard sizes in the industry. If you look up form factors, mini tower are 4 expansion slots, full height and can be micro atx or btx. The only concerns are length and width. Hdd cage will likely be the limit for length, and if it's btx the cooler will limit it to a single slot (width). Mobo is always irrelevant to if it fits in a case because height only has 2 sizes for gpus, half (aka low profile) and full. All 580 are full height as half is only for low tdp gpus.