If you have access to Advanced Machines in a modpack, using them is strictly superior to using overclockers even with the constant (trivial) power drain they exert on your system. Their standard speed is ideal for general use provided it's not a GregTech dust you want smelted.
Not necessarily if you're playing on a server. If you keep the machines always loaded, the tiny energy drain adds up over the hours. The power usage of normal machine only scales with how much stuff you throw in it. For advanced machines it also scales with the time it's sitting there doing nothing. In fact, over long periods of time (think days), advanced machines will draw several orders of magnitude more power than even heavily overclocked standard ones.
Your solutions pretty much are:
- Do not load your machine room (but then it can't process stuff while you're gone).
- Devise a complicated system that will load/unload the room as needed.
- Turn the machines off when they're not being used (but then you need to wait for them to spin up again when you need them).
In such circumstances I prefer using just overclocked normal machines - although the spike power drain per item is higher, the overall drain on my energy reserves is much less.
(P.S. if you consider energy free, just overclock normal machines to process an item every tick, and they will be clearly superior.)
