[Ultra] In what Situation should it boost up to 2.56GHz?

ektor5's CPU-Z result is from J3710, a Desktop grade Braswell CPU. No idea what machine is it? Or is it a CPU-Z bug?
UDOO x86 Ultra is using N3710, a Mobile grade Braswell (per documentation.)

 

By the way, I really like that community members actively find out this stuff and check if what is delivered is what was promised.

 

Ok, so somebody who has Windows installed give CPU-Z a try and see what it reports. I only have Ubuntu 16.04.2 installed...

 

Found the reason:

Intel renamed the CPU N3710 is now J3710
CPUID signature: 406C4
http://www.anandtech.com/show/9806/intel-introduces-new-braswell-stepping-with-j3060-j3160-and-j3710

 

BTW, reading that article, N3160 is now J3160.
Maybe CPU-Z will report that as well.

 

Regarding CPU Burst mode

https://forum.synology.com/enu/viewtopic.php?t=123367
https://www.linuxmintusers.de/index.php?topic=24566.0

 

TL;DR; ?

 

Short summary as I read these links:
it seems that "burst mode" support currently is a black art and evolving, and not limited to this SBC board/community.
Better let the people who's willing to invest time and $ to get to the bottom of it.