Is the graphics card in a Mac Mini really that good? Seems there would be cheaper ways to buy commodity hardware and put the savings towards a better graphics card.

I know I'm parallel-commenting here the guy himself, but seriously, I believe this is just what happens when you either have too much money, are too lazy, or both.

I am pretty sure they could have come up with a basic MoBo+GPU+CPU+RAM combo to buy from a large distributor, assemble them in series in no-time and get a vastly cheaper and more powerful farm.

Walking around buying mac minis a dozen a time to build a data center is just silly in my opinion, whatever the reasoning.

You are not wrong. And we were very well aware of this. However, we found the reality of the problem being solved is much more about network latency, routing, and caching than actual graphics processing throughput. Our pain points have been very different than what you are prescribing as a better course of action.

They do a fair enough job for what we needed. Really, it was more about what we could get quickly, with a certain expectation of consistency, just to get us moving forward.

The latest Mac Mini uses the HD4000. It doesn't come with a dedicated graphics card.

Its rated around 100 megahashes. A 6990 gets you 800MH.

I'd have to do the math, but the Mini is very power efficient¹, so perhaps it was just enough graphics capability for the watts it consumes (11 watts idle, 85 watts max, if I recall correctly)

¹A lot of data centers these days bill you based on the power + bandwidth you consume, not the # of U's you use in a rack.