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Main article: Overclocker Upgrade (IndustrialCraft 2)

Overclocker Upgrades can be used to speed up machine processing, and are crafted like so:

Each Upgrade decreases processing time by 70% but increases power usage by 60%. Adding more than 1 upgrade stacks the effects, so adding 2 would result in a processing time of 49% compared to normal, but uses 2.56 times more power. Adding more provides diminishing returns; for example, adding 4 Upgrades would drop the processing time to 24% but the power cost would be 655.36% more than normal.

There is no need to work this out manually, as hovering over Overclocker Upgrades will display in their tooltip how much of an effect adding it would have on a machine.
For the previous two examples, the tooltips would show:

Processing time can never exceed more than 1 process per tick, meaning adding more than about 12 Overclocker Upgrades to any machine will waste power, as although the speed of the machines cannot exceed 1 process per tick, it can still draw an extra 60% power per Overclocker Upgrade.