Have you even tried putting a stack in? It is about the least sensible thing in the world!
NOTE: The following statistics are based off of the Macerator, which has a 400 tick default operation length, and 2 eu/t default.
1. Anything above 32 clockers is completely useless as the code just sets the rate to 32 when its anything above 32
2. With 32 clockers the energy consumtion per tick is equal to about 862,880 EU/t
3. With 32 clockers the tick rate is about 1/250th of a tick, which gets set to 1 tick obviously, so even for the Macerator which has a very long operation length, the max effective overclockers is 17
4. Get the idea here?
EDIT: Also in the Macerator, with those 17 clockers in it you will need 1971 eu/t or operation and it will do one operation per tick.
Yeah you could change a simple thing, make them not multiply but add to each other and change the values a little bit. So two overclockers is +100% Energy-usage and 60% faster.
With 17 Overclockers one process uses 1971 EU. Without it costs 625 EU. This is only about 3 times more expensive. I don't really know how to get 1971 EU/t inside the macerator, but the energy-usage isn't that high if you base it on the work done.