One more thing to note is that gamer cards aren't meant to be abused like workstation cards are. You can leave a K80 running at full blast for a week doing stuf

One more thing to note is that gamer cards aren't meant to be abused like workstation cards are. You can leave a K80 running at full blast for a week doing stuff, but the same workload will significantly reduce the lifespan of a high-end gamer video card. They're meant for gaming sessions that last a few hours with some outliers going for maybe a full day, but not much more than that. If you really have a tight budget and need to use gamer cards as workstation cards (e.g. a two-person startup that needs to crunch things on 4 GPUs), find yourself some aftermarket coolers, preferably liquid cooling.