The Tesla 500te br is a cheap, low quality generic PSU which I definitely would not recommend you use to power an R9 270 from.
There is more to CPU compatibility than just it's output wattage. See the Best Solution post in this thread for guidance:
http://www.tomshardware.co.uk/answers/id-1922284/power-supply-270-system.html
Remember, if an inadequate PSU is used and it fails, it can kill other components too, including your shiny new GPU card. So trying to avoid having to buy a new PSU is false economy when that happens.