Extruder Stepper Motor Getting really hot. TMC2224

[Sneakers]

So a little backstory. I've got a Geetech A30 and A10. I had been using the A30 with upgraded TMC2224 drivers. However, because the power supply died in the A30 (Geeetech is sending a replacement) and I've been unhappy with the Smartto Firmware I've retired the A30. At least until Marlin can be compiled for the board or I feel like swapping out the board.

Anyway, I transferred the TMC2224 Drivers to the A10 and it is running the extruder stepper way hot. XYZ are running just fine at a Vref of .8 (Approx 60c for XY, Z is 49c). I had the Extruder Vref set at .8 and the motor reached 80c after just 30 mins of printing. I've turned the Vref way down to .34 and finally getting the motor to stabilize at about 71c.

I'm confused as to why this is happening. When I used this same driver in the A30 (12v Version) with a Vref of .65 the extruder motor heated up to about 42c. Any thoughts?

The TMC2224 is in the same family as the TMC2208. You can read a little more about it here: http://www.panucatt.com/product_p/sd2224.htm