(I'm the datacenter manager at imgix and wrote this article)
Nope, it's not ridiculously expensive. The GPUs in the Mac Pro are actually an exceptionally good value per gflop (when I last did a comparison a few months ago). GPUs that will work in servers are not cheap -- a comparable AMD FirePro S7000 is $1000, and the Mac Pro has two of them.
There's the cost of having these Mac Pro chassis fabricated, but they're passive hunks of metal with some cabling run. Nothing too expensive there, and economies of scale are on our side.
The Mac Pros are at least 5x more cost effective than Mac Minis (per gflop, total operating cost), and they're substantially more cost effective per gflop than doing something like EC2 G2 instances. My estimate is that moving to Linux servers would save us about 10-15% per gflop, but that could easily be eaten up by the engineering time needed to migrate.
>Couldn't you achieve the same thing using cheaper PCs?
They say "Parts of our technology are built using OS X’s graphics frameworks, which offer high quality output and excellent performance". So they couldn't achieve the "same thing" in the sense of running their software on racked computers, because it won't run on PCs, and if you're thinking about expense you'd have to consider the cost of making the software run equivalently well on PCs.
I'm really curious about any study/compassion between OS X's graphics frameworks vs other open/closed source solutions available. How 'output quality' is measured?
At this scale people do all sorts of ridiculously expensive things, like purchase six+ figure software licenses, or buy hardware from OEMs that charge an arm and a leg for "server" quality when it's no different from those charging 33% less.
So that's to say, that if there's an actual use for OS X at this scale, it's far less financially crazy than a lot of things that go on in data centers.
"Parts of our technology are built using OS X’s graphics frameworks, which offer high quality output and excellent performance... Building on OS X technologies means we’re dependent on Apple hardware for this part of the service, but we aren’t necessarily limited to Mac Minis."
Nope, it's not ridiculously expensive. The GPUs in the Mac Pro are actually an exceptionally good value per gflop (when I last did a comparison a few months ago). GPUs that will work in servers are not cheap -- a comparable AMD FirePro S7000 is $1000, and the Mac Pro has two of them.
There's the cost of having these Mac Pro chassis fabricated, but they're passive hunks of metal with some cabling run. Nothing too expensive there, and economies of scale are on our side.
The Mac Pros are at least 5x more cost effective than Mac Minis (per gflop, total operating cost), and they're substantially more cost effective per gflop than doing something like EC2 G2 instances. My estimate is that moving to Linux servers would save us about 10-15% per gflop, but that could easily be eaten up by the engineering time needed to migrate.