[sliverstorm]

I run a 2-GPU tower and make a couple bucks a day with zero upkeep effort on my part.

It's not totally vanilla hardware like the 15-watt laptop I'm typing this on, but it is common enough I happened to have it already.

With ASICs the barrier to entry is five figures. (Most of the cheaper ASICs have terrible payoff timelines) With GPUs the barrier to entry is far, far lower. You won't make it rich on a $150 GFX card, but you can make some revenue.