I'm Playing Minecraft on My New 5K and the CPU is Maxed Out!

Hello,

I just Recently Bought my iMac 5k and loaded Minecraft onto it. So i start playing minecraft and I see in my activity moniter that Minecraft is Using 101% CPU and the fan is running at 2200 RPM, and Everything thing returns to normal, no sound of a fan or anything after Minecraft is closed. This is Very different to my Old iMac (The Late 2013 Model) Which Ran Minecraft perfectly Fine! So I don't really Know What to do right now and was hoping someone out there could help me.

Thanks In Advance,

Specs:

iMac (Retina 5K, 27-inch, Late 2014)

Processor: 4 GHz Intel Core i7

Memory: 32 GB 1600 MHz DDR3

Graphics: AMD Radeon R9 M295X 4096 MB