Playstation 4 Graphics vs HD 7750 Graphics

Solution
Note that the PS4 doesn't actually run games at 1080p. The PS4 defaults most games to 900p because it simply cannot output the graphics for 1080p while still delivering performance.
With that said, since the PS4 can barely handle 900p, I would say the 7750 at 768p will have better performance if you actually get the PS4 to run games at 1080p.
Now if you change the question to the PS4 @ 900p, it really depends on what processor you have with the 7750. Lower resolutions usually puts more strain on the processor and remove some of the strain off the gpu.
Note that the PS4 doesn't actually run games at 1080p. The PS4 defaults most games to 900p because it simply cannot output the graphics for 1080p while still delivering performance.
With that said, since the PS4 can barely handle 900p, I would say the 7750 at 768p will have better performance if you actually get the PS4 to run games at 1080p.
Now if you change the question to the PS4 @ 900p, it really depends on what processor you have with the 7750. Lower resolutions usually puts more strain on the processor and remove some of the strain off the gpu.
 
Solution