does anyone know how much bitcoin / watt the R9 270x can push out? im considering bitcoin mining when im not gaming and wondering if it would cover the cost of electricity.
There is little to no value in mining on such a small scale - you'll hardly earn anything and risk the chance of damaging your GPU which wouldn't be worth it unless you're still under warranty. Anyway you don't want to be mining BTC, try LTC or some other scrypt with BTC you'll earn ~ 0.