I get almost half frame rate with full light size 80 fps, compared to small light size 155 fps on my gaming rig.
you do want high fps to avoid stutter / input lag to get a smooth flipper-ball action
V Sync TURNED OFF, forced in the gfx driver
This is crucial, much less micro stutter/lag, much more fluid gameplay.
but I don't think you can reduce fps to get full light size, it is more gfx memory related as described in above posts.
Someone has yet to explain to me the advantage of the full light size / show some pictures.
I did some comparison screenshots, but still could't see a difference...