>=500Mhz microcontroller that works with arduino sketches? I'm looking for a decently beefier arduino, but from what I can tell by using google the best I can get is up to 80mhz clock speed. I need something closer to or higher than 500 with more ram, I found the Intel Edison but it runs linux, what I'm looking for is something that is bare metal like the arduino.
I need the higher clock rate for faster calculations and more ram for storing vertex information for a 3D renderer.
Thanks for your help everybody.
I would guess that the Teensy 3.6 is the beefiest Arduino available right now. It runs at 180 MHz. Now clock speed is not everything. This can be illustrated by Arduino-Scheduler and context switch time for the supported boards. 

Cheers!