That's cool, what was the CPU usage like on that machine?
You will notice the 120 frame rate does use a bit more CPU.
I think it peaked at some 9%.
Which is impressive, and a testimony to the coding qualities of both Steven and you.
Surely a higher fps will increase cpu load.
But in my personal opinion having fps at 120 will not cause any real-world issues to anyone on any system.
(I think people only have complained when it was somewhere above 15% ?)
And for the rare occasion that somebody thinks the cpu load is too much to their taste, they could modify the .xml.
Set it to 30 and accept mediocrity.
Rethinking things, I would vote against adding an additional option for 30/60/90/120 or Ultra Smooth™
Let's favour Quality over Quantity, leave the plethora of headache-inducing options to foobar2000 users, and keep things as good and simple as possible?