I didn't really notice 8.1 being slow, but I have not used it much, I usually stick to 7.1 or 7.5.5. I don't have another point of reference on a machine it is really intended for, but I didn't notice any significant lag opening windows and such. The system folder needs to be trimmed down since it is super bloated. The annoying thing about doing an install for another model (or any model) is there ends up being a lot of unnecessary add-ons. A list of what is needed for the SE/30 to run would be helpful for those not totally sure what everything does.