First of all, I use a old PC. Intel Pentium Dual Core at 2.00 ghz and Intel G41 as the iGPU.
When changing from marco (in Ubuntu Mate, but GPU compositing in general as it happens with other ubuntu 17.10 flavor I’ve tried) things run fine, no tearing, normal performance.
Then some time into actually using the PC things start to slow down like firefox lagging and choppy performance overall. What I see is that CPU 2 is usually running 30% more when compared to CPU 1. Then it justs slows down to a crawl (not mouse input though, it still normal) and the high CPU 2 usage stops. The only way to recover from this (if I manage to get to Mate Tweak with the sluggishness) is switching back to Marco (software) or no compositing at all. And if I don’t do that rebooting the PC solves the problem temporally.
I’ve tried everything, even deactivating the Intel microcode in propietary drivers but one moment later rendering slows down like trying to run Skyrim on a pentium 4 CPU. Again, this happens on Xubuntu and Kubuntu (don’t know the others) but Ubuntu Mate is my main one 
And yes, this does not happen on 16.04 as far as I know