I just upgraded to ubuntu 15.04, and not only was dual monitor capability lost, but compiz seemed to make the CPU run at 80% despite there was nothing running. I installed the compiz editor and tried some things, but can't figure out what's wrong.
Specs: Dell Optiplex GX 755 4 Gbs DDR3 RAM Intel Core 2 Duo Processor @2.66 GhZ ATI Radeon HD 3470 256MB PCI Express x16 S-Video/ DMS-59 V