Default Why is CM slow these days

Anyone else think that pure stock ROMs outperform cyanogenmod? I've had a couple of phones where this is the case, my games chug at low framerates where on stock they're smooth. This includes stable releases and I've yet to find a ROM smoother than stock since the single core days! Anyone know why this is?

Sent while my supervisor wasn't looking
If you don't want it ROOTED then DONT LEAVE IT WITH ME!