Best graphics card for 768p

[appropriate username]

I have already posted a thread like this except I wrote the wrong resolution which might be important. And sorry if these questions might seem a little unclear.
What would be the best gpu for 768p resolution (1366x768p.)?
im not sure if all graphics cards work at 100% capability at this resolution, usually higher end cards as it seems (the card not reaching full potential in performance). Would this happen with the gtx 900 series as an example? Could these cards be bottlenecked somehow? (This is sort of a side question

 

[scaniatruckfan]

An R9 270X will be enough for 768p

 

[appropriate username]

thank you, inputerror