the R5 230M (or M230) is comparable to an HD 8570 which by AMD's naming scheme is clearly less powerful than the HD 8750.http://www.notebookcheck.net/AMD-Radeon-R5-M230.108655.0.html
So go for the HD 8750m.
The HD 8750m should be able to play most games at 1366 x 768 on medium settings (and high on older
and perhaps more modern and demanding games at 720p with lowered settings.
Hope this helps!