Comment 28 for bug 1386721

Affects me too.

I have Unity and 14.10 upgraded from 14.04, Dell E7240 notebook with Core i7-4600U and integrated Intel Haswell-ULT video.
First the problem seemed to appear after upgrade when I decided to try unity8 and installed it packages (the graphics remained slow even when I was in classic Unity session), and everything disappeared, when I removed unity8.
Now the problem reappeared, and I found unity8 installed again. So I removed it with all the stuff depended on it and the is likely went away again.
WARNING: if anyone would try my method, it removes indicator-network. I myself prefer nm-applet, it requires network-manager-gnome to be installed.