...on a device that weighs about 10 grams with a heat capacity likely around 0.4J/gram-degrees-C. 10Ws for such a device if I did the math right is around a 2.

...on a device that weighs about 10 grams with a heat capacity likely around 0.4J/gram-degrees-C. 10Ws for such a device if I did the math right is around a 2.5C/sec rise in device temperature.