Frequency (in Hz) that should try to complete individual work chunks. Higher numbers may run slower but will provide a more responsive system. Lower may be faster but more laggy.
default 60 (corresponds to 60 fps)

Period (in milliseconds) to check for scene updates

Change how fast the view randomly moves around

Make particles bigger or smaller

Make particles bigger or smaller when using uglier particles

(These parameters are what do you mean)

On my system the parameters have no observable effect (my nVidia is not used to render desktop and I do not have screen-saver).

I believe "Frequency" controls the kernel size,
and the rest controls the screen-saver.

I set the "Frequency" parameter to 1, because "Lower may be faster" and I have no lag.

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I just use the default 60 for frequency since that's the refresh rate of my display and I also game on this computer, et cetera, so I want to maintain a fairly responsive system.

I'm not sure what difference it actually makes though and wouldn't mind further clarification.

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