I'm experiencing the same approx. 65fps limit. I see another user has previously mentioned the blur-busters CRT Beam-simulator algorithm - to function this is essentially inserting additional frames (similar to black frame insertion but more sophisticated) to facilitate a reduction in motion blur. Although some of these shaders seem to have made their way into the app through the retroarch library, I'm not sure that they function in the current beta as intended.
Additionally I understand some of these CRT shaders require additional steps such as phosphor masks. I'm very impressed for example by the death to pixels presets: Cyberlab death to pixels
Some of the best screenshots within that set of presets have really beautiful RGB 'sub-pixel' layouts that I believe requires additional steps.