I noticed that a geothermal generator hooked up to a storage device that's powering low-draw machines with the "on-off-on-off" behavior causes a lot of lag in addition to being annoying if you have the sound on (was lowering fps by about 15).
With the latest version of RedPower, the two-storage-block method of preventing this behavior is obsolete. You can just set your storage to "emit if full", then use that as an input for a state cell set to 60 seconds or whatever you want the minimum cycle time to be that in turn controls a splitter cable between the geo gen and storage.
The same setup works (with the state cell output inverted) to make a mass fab use spare power but on a less laggy cycle time.