Bullshit, even Radeon manufacturers require 500 watts.
https://www.visiontek.com/graphics-cards/visiontek-radeon-r9-380-detail.html#system-requirements
http://www.gigabyte.com/products/product-page.aspx?pid=5462#sp
If you think that you can drive around a Corvette on Prius tires, then yeah, go right ahead. :lol: