UP-BOARD CPU throttling locked to x6 under Windows 10 iot. System very slow!

amenon

After a clean installation of Windows 10 iot and all the available drivers for UP board (4G/32G) the system runs very slow.
BIOS version UPC1DM23_EFI
The Windows reported CPU is limited to max 33% and with CPU-ID the bus is rated 80MHz and the multiplier to x6 (so 480Mhz equivalent speed).
How can I unlock the throttling ?
What could be wrong on settings somewhere?
BIOS settings reset to defauls, speedstep enabled (EIST, and Turbo on)

Windows iot enterprise LTSC ver 1809 build 17763.1852
Cores temperature are all below 55°C!

See attached screenshots.

Thanks a lot for helping
Best regards,
Alessandro

amenon

Update:
we've found that the problem is due to the "IGD Turbo mode" settings under NorthBridge section. That setting is NOW set to disable (UPC1DM23) instead of Enabled.
It is not clear to me why the IGD configuration interact with the CPU throttling, but enabling that setting the CPU clock restart working correctly up to 1.4GHz (1.6 duriing overloads) and the multiplier varies correctly.
NOTE that in the previous BIOS versions ( i.e. UPC1DM21) this setting was enabled by default.
No changelog notifications on BIOS hystory version file.

@ UP board team: please could you check this and explain why this setting determines the CPU main core underclock?
Many thanks
Best regards