So I'm going to shortchange you and ask you to look at and try the Geforce 750 that is widely known to not require a replacement PSU. The question of 235/300 is so well done that again I'll just end with a link. Bob

-> http://www.amazon.com/EVGA-Superclock-Dual-Link-Graphics-02G-P4-3753-KR/dp/B00IDG3IDO/ref=cnet

http://www.tomshardware.com/answers/id-2125599/300w-power-supply-evga-geforce-gtx-750-superclocked-2gb.html is one of a thousand posts about this.

And no, it may not deliver what you asked but it's the best I know of without changing case, power supply and wallets.