iFixit has done a robust teardown of the iMac Pro, and we finally have a complete picture of which components can be upgraded and how easily. Additionally, the teardown found an impressively large cooling system responsible for the silent running we experienced when we saw the iMac Pro up close last month.
As we noted then, the Fusion Drive setup with a standard desktop hard drive from the standard 5K iMac is gone, as is the hatch that allowed upgrading the RAM. These changes and others have made room for a massive, dual-fan cooling system that Apple says offers 80 percent greater cooling capacity than we saw on the existing 5K iMac. There’s also a bigger air vent on the back of the machine (see our earlier gallery below for a glimpse at that). Thanks to all this, the machine runs very quietly and is not warm to the touch, except right around the vent.
Source:: Arstechnica – Gadgets