Loading a topology in GNS3 can consume a massive amount of CPU. To decrease the CPU usage and make the GNS3 experince bearable i carried out the following steps:
Load a Router/IOS > Start it and open a terminal.
At this point select the Idle-PC value and let the PC decide the option for each IOS image independently. I did this for each IOS, i also changed the Idlemax value = 100 too. 
MystaJoneS 