Well, 1/8th is 12.5% which is 13% when rounded. So one core is being maxed out. Pat finding uses web-workers so do a lot of pathfinding to Engadge the other cores.
To only use 1-core today is terrible, that means for a 4-core mobile device u can only use 25% of it's CPU Power. Mobile devices don't have much CPU power to start with so to be limited like this is insane.
Let's look to the future, we'll see mobile devices with 8-cores and 12-cores, which have already been reported in the tech news, yet the GHZ per core is not really increasing becos of heat and power usage limitations, so that means for the next 5-years our Construct 2 games cannot be any more complex than they are now, they cannot be any better becos we are currently limited to 1-core processing - PATHETIC!
All the competitors will roll over Scirra if they do not fix this! I play a Unity 3D Game on my PC and it's using all 8-cores of my CPU.