Factorio Forums

Productivity boosted labs seem to get a speed boost for free, resulting in much faster research overall.

Hello, could you be more specific?
Productivity modules add bonus production, so yes, it in fact makes the production faster, but the bonus is much smaller compared to using speed modules.

I also noticed this, productivity modules not only add purple bar, but also speed up the green bar. When you insert 2 lvl3 purples, the speedup should be clearly visible.

You are right, now I found the reason of this (a bug). It will get fixed.