Eh? I'm not mining anything on anything, just pointing out what the commenter I replied to left out.
If power is free then any hashrate is profitable. With "typical" power prices you basically need ASICs. In the middle there are myriad possibilities, and many miners have access to very cheap power (eg during hydro gluts in monsoons).
I was asking what hardware you were talking about. "You should mine a different cryptocurrency" wasn't meant as something specifically for you the commenter, but as a recommendation to everyone in the world. Theoretically you'll get something by GPU mining bitcoin, but it'll be tiny. You shouldn't do it. Instead you should use that GPU to mine ethereum. That'll be much better.
As an example, the AMD Radeon HD 7870XT[1]. It gets 346 Mh/s for bitcoin, which is $0.00004308/day[2]. It gets 14.5 Mh/s for ethereum, which is $0.3508/day[3]. So you get 8000x more by mining ethereum.