Does resolution effect frame rate

Yes, a game would run faster with a lower res, and also, a high res, affect the frame rate of a game if your computer isn't fast enough (<1~1.6GHz).

However, it also affects the appearance of certain games (e.g Chrono Cross), where the backdrop doesn't seem proportional to the PSX native res.

Check out Kane's Domain for details.

Rzetlin, i suspect there is a deeper meaning behind this question. you are not ignorant; you obviously know that not everyone can run their games at 1600x1200 because the hardware isnt fast enough. im sure you've experienced that problem with the GF2mx already.

did you mean something else? if not, then the answer is yes. yes the frame rate is affected by the size, and yes a smaller resolution gives more FPS. for optimal PSX emulation i'd suggest playing at a multiple of 320x240 (like 640x480, 1280x960, something like that)