Here is the pace graph from Garmin Connect for my run this morning. You see that the Avg Pace is 8:16/mile which is correct. What is odd is all that pace data that is slower than 8:16/mile while very little if any is faster than 8:16/mile. One would think that an average pace would have an equal amount of time slower as well as faster. I think this graph does a good job of illustrating the problem with the 910xt instant pace. Yes, this is with the 2.40 firmware. I even did a full reset of the device and left it outside for 30 minutes.

http://imgur.com/gfY3H