Well, overdrive only doubles the power consumption according to stats. 2 AMC blocks: 300 power consumption, now connect them to 2 Overdrive blocks and they have 600 with double the damage, just like I said so it has the same effect as just putting 4 AMC blocks on the ship, that's my main issue. I wonder if the stats displayed in the weapons tab are simply wrong.
EDIT: INDEED! The weapon stats ARE wrong. It says a 100% ionized weapon does 300 damage, but it actually does 600 against shields! So FOUR times its damage. I have 10 AMC blocks and 10 ion blocks connected, the AMC blocks damage is 150, 20 AMC blocks would do 300 though. Apparently the stats treat the effect blocks as if they were normal AMC blocks, but the effects actually work. So yeah, ion DOES make a weapon do FOUR times the damage against shields at 100%.
That makes me wonder if the stas for the ion defensive effect on shields either is wrong, too, or if you just only need very few ion blocks. (Which would make sense since you need A LOT of shield capacitators to get any worthwhile shields, so it would make sense to keep the space requirement for hardening them rather low.