xcode 6.4 + OX X 10.10 Yosemite - Problem with all simulators

Anyone experiencing problems with Xcode 6.4 simulators? at first I though it was my fault and I was looking to find which part I messed up in my code, but when I go an actual device to test my project everything seemed fine. What I did is upgraded to to 6.4 yesterday evening and since then I have this problem. Tried to update 10.10 OS X but this didn't fix anything

Solution 1:

Resolved the issue. As I am running two monitors I was trying to open a new tab in safari, while Xcode simulator was selected. Cmd T triggers the simulator to run in slow motion for further testing. Nothing to do with the new Xcode or OS X update