The Efficient Skill bonus from two or more Efficient BOffs (and, possibly, the Efficient Trait, on your Captain) stacks.
Additionally, the only consoles that 'diminish' with stacking are Armor Consoles (and the +35% Shield Capacity booster, of which you can ONLY run one). All other consoles stack linearly.
To be fair, the Armor Consoles stack linearly, as well, but the formula that governs their value makes it appear that they suffer from diminishing returns.
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Additionally, the only consoles that 'diminish' with stacking are Armor Consoles (and the +35% Shield Capacity booster, of which you can ONLY run one). All other consoles stack linearly.
To be fair, the Armor Consoles stack linearly, as well, but the formula that governs their value makes it appear that they suffer from diminishing returns.
Hope that helps,
-Big Red