Apple will release a professional version of its all-in-one iMac desktop computer with a $5,000 price tag on Thursday. Up to now, all-in-one computers in general and iMacs in particular have been seen as stylish offerings for home and family, but Apple has changed that in a big way with the iMac Pro. Apple has given the Pro workstation-class graphics, processors, storage, memory and I/O -- all without increasing the size of the iMac.