[aerogems]

I'm wondering about the PowerVR chip. What is that based on or similar to? Is that yet another architecture? 

 Doing a quick Google search, this is the company that used to provide graphics chips to Apple for the iPhone and iPad. Looks like the last model they did was the A10X, which happens to be the same chip in the ATV4K. According to Wikipedia, the ATV4K uses Series 7XT GT7600 Plus with 12 cores/clusters running around 900MHz. The new Fire TV Stick is using the Series8XE GE8300, which according to Anandtech will be probably roughly comparable, maybe a little weaker. So the AppleTV 4K or current gen iPad Pro's are probably the closest analog, and it looks like it would sit somewhere between the ATV4 and ATV4K (closer to the ATV4K) performance wise.