Excellent post! I've already got some experience with the Odroid XU4, and they're great boards that have gone completely under most people's radar! They even recently released a fan less version that looks very promising in regards to stock speeds.
Pretty interesting that you were able to switch to TNgrid without errors since they don't officially support Linux on ARM (AFAIK).
Yah the Odroid is very impressive. Here's the TN-Grid applications list, which shows the Linux/ARM support. I've been confused in the past because official BOINC documents like this are very out of date.
Only negative thing i have about it, is that the build quality can be a little dodgy. I've been through a lot of them at work, mostly for drone beta/prototype applications, and some of the boards were pretty badly made (bad soldering loose connections on the I/O stuff like that). Most are just fine though.
I have found that the XU4 throttles down to 1.9ghz (of a max of 2.0ghz) almost all the time. Even with the cooler on the board, plus another fan, plus 22C ambient room temperatures.
Did some research on the throttling down to 1.9GHz, and it seems the stock cooler simply isn't good enough to handle all cores on full load. I'm experimenting with some water-cooling at the moment, I'll post my results when I'm done testing. Might even try to OC the bastards if temps look good :P
Cool, I look forward to seeing what you discover!
I haven't noticed that, but we also don't monitor the clock speed that closely so I could easily have overlooked it. It's not too bad, but a little annoying if it's consistent though.