POWER was historically the architecture for "I don't care about efficiency, I just want a fast machine!". This hasn't really changed. For some applications they are still substantially faster than any x86 system, but they're almost always far less power efficient. That's why they're not widely adopted in data centres.

> That's why they're not widely adopted in data centres.

I don't think that's the entire picture..

If you're running systems at full capacity, throughput vs power consumption becomes a relevant equation - e.g. if the chip runs code 2x faster but is 1.5x less power efficient, I'm still saving .5 of power to get the same data processed.. Not sure of power consumption specifics for POWER, but they've been about to 4x faster than PC for some workloads.. E.g. 4GHz CPU + giant cache and 4x the registers will tear through matrices like a hot knife in butter... Also, there's the question of density vs performance - e.g. I only need X sq units of datacenter to process this dataset within the timewindow..

Also, historically the only people 'needing' power and willing to pay for it were companies with deeper pockets who wouldn't mind shelling out for AIX and the rest of the IBM stuff that goes along; linux is to some extent an 'afterthought'/'second tier' OS for this market though that has been changing in last few years. People using IBM or AIX have typically tended towards being risk averse and have been on POWER for ages; for everyone else, people haven't wanted to spend the money to migrate to a platform controlled by one company, etc.

That may be a con for a data center or battery-powered device, but not so much for a workstation.