In SSTU, whenever you deploy a *2-piece clamshell* fairing I get heavy fps drops. With a 3 piece clamshell I get less significant fps drops, and with the non-clamshell no significant fps drops.
Actually this has to do with how many *sections* I put on the fairing. And now that I've tested this with the stock fairing, I can say it is not SSTU's issue, but rather a squad issue.
Well lesson learned: too many sections(not sides) on a fairing cause fps drops.
Thanks for letting me blog this lol. I was trying build a rounded fairing ala Soyuz when I ran into this issue.