disclaimer ---- previous post...
That 5% to 20% estimate means, your mileage may vary. But me, for one, am not going to sit there, with a stop watch, timing frames, as I'm tweaking cpu settings. On the surface, it appears to make your machine marginally faster, but then when you consider the "babysitting" aspect, my inclination is to say "nah"... it ain't worth it.
Finishing up a 72hr workunit in 61hrs, isn't worth it, if you have to run through all of your cpus, to make sure that they're all reset, and tweaked again.
Fire them up, and forget them. If you don't see one show up in the 7 day period, hunt it down, and find out what's wrong.
This is fun, but it doesn't have to be obsessive.