I can't seem to get my voltage changes to stick. Whenever I go back into the voltage settings they have reverted to default. I'm on the latest UberKernel and can overclock to 1.9GHz fine.Running 2.2.4 on a Pre3.
Interesting read and the guys clearly put in a lot of effort. Still i'd be surprised if something isn't amiss in the setup. Chip makers wouldn't go to all that effort of setting different voltages for different speeds if it wasn't needed.
Looks like there are a few things need to be double checked before the result stands.
1) Effect of CPU load. ARM chips are really aggressive at turning off unused blocks when not being used.
2) Possibility that the UV settings weren't being enabled properly.