welcome fellow animator ! I run shroomstudio CHECK us OUT...yeah it's the heat that's the problem ! We talked about putting a couple of our old machines out to pasture with mining.. we use Dell Workstations with Xeons and I'm sure the GFX cards in them are still up to the job..
I think the nicehash is a really interesting way of using your machine for obtaining bitcoin without hashing your socks off.. agree, I think your $2 per day will be worth quite a bit more in the future.. best of luck to you !!