suomy

You don't even need to do the rack-unit-height-divided-by-mini-dimensions math to see this is an power and efficiency win for data centers and colocation farms. You can tell the new mac mini is smaller than the old just by looking at it. At the end of the day, the KPI for hardware design in this case is a volume play: computer per cubic centimeter.

That said, I still did the math. On their side, 5" is less than 5.25 (3U), and 3U divides evenly into 42u. 

roundaboutnow said:

I was hoping the height would stay under 1.75" for 1RU rack mounting. At 5" wide, I'd be able to get three in a row on a 1RU rack shelf, but now I'd need 2RU, wasting a fair amount of space...

Unfortunately, us wee little enthusiast rack-mounters and our obsessions with 1U is just not their target market. :-)

Even if a 1RU fan tray were mounted above each 3RU row of minis, that would be a lot of horsepower and a lot more I/O in less rack space than the 5RU Mac Pro!

I don't think that fan tray would be needed. The thermal design is such that airflow is still front to back, so with units stacked (and the whole set tipped sideways) it should allow for a modest gasket design to formally divide and seal the front of the enclosure (intake) from the back (exhaust).