I have both a powered hub and a power adapter rated at the correct voltage per the RPi suggestions...so not sure quite what to do. I just went ahead and got a used mini pc, which I can always use for other things if the Rpi ends up working in the future.
Use this one to be specific, its 5.25v and it wont lose that v when you put a load on it. Best one out there for a PI. Im now at at 6 days without a crash on my Pi with 4 miners running cgminer. Power Adapter really makes a difference.
http://adafruit.com/products/501