Will Radeon R7 250 run on my pc??

[Bayezid13]

The power supply of my pc is 450 watt. But the problem is it isn't from a renowned brand. The name of the brand is 'vision'. Websites say r7 250 needs 400 watt. But I heard that non branded psu like mine supplies less than they write on their product. My question is will I be able to use r7 250 or not. Please don't tell me to buy another power supply? I can't afford that

 

[SherbetAddict]

Is the 450w rating continuous or peak?
I wouldn't trust anything with a peak rating with my clock.