That PSU is perfectly fine for what your hooking up to it.
R9 270 requires 24 Amps on the 12v rail , a 500W PSU minimum & 1x 6-pin PCIE
It has a very healthy 480W/40amps on the 12v rail + 1x 6-pin PCIE, which powers your card etc...
Just don't do any serious overclocking, as keep in mind...