Thanks for joining the NUC community.
I understand the BIOS showing 30% of utilization and this is only present when the NUC has been on for several hours.
I am afraid, I was not aware of this problem but I would like to know more about it and probably find a fix for your case.
- Does this issue happen with earlier BIOS version? If so, Can I have BIOS versions?
- What is the monitoring software you are using to check processor usage?
- Have you noticed this problem with same NUC models? Or different NUC model numbers?
Initially I used the desktop CPU/Memory gadget and Task manager to monitor the CPU load, I then used a program called Process Explorer to track down the individual process. After noting the process was the USB 3 driver, I then measured the system with and without the driver installed several times. In every case the CPU started to idle at 27%-30% when all USB connections were removed or powered down with the USB 3.0 eXtensible Host Controller driver 126.96.36.199 installed. As soon as I inserted a thumb drive or powered up the DAC the CPU idle dropped to ~1%
My test configuration is simply a high end audio DAC with a 2.0 USB interface that is powered down when not in use. The NUC is powered 24 x 7
The idle issue can actually happen in less than 2 hours and does not appear to be temperature related in any way. A re-boot will always fix the issue until a USB 3 port is used again. The issue is indifferent to which of the front or back USB ports are used.
I initially found the issue running BIOS Ver.26 . After updating with Ver.27 I confirmed the issue was still present.
My installation is headless and controlled using Event Ghost running TCP commands. The ONLY connections to the NUC are one USB and the Ethernet connection. All measurements were made utilising Microsoft Remote Desktop. In respect to software applications and drivers installed, the NUC has a DAC driver and an Audio player called J River Media Centre. Aside from the Process Explorer diagnostic software all other drivers are those recommended and supplied by Intel.
I only have access to one NUC system that supports USB 3.0. The system I have has been running flawlessly for the last three days with the USB 3.0 eXtensible Host Controller driver removed.
Fortunately my application does not need USB 3 speeds, nevertheless it would be in everyone’s interest to resolve the anomaly.
Thanks for the update.
You mentioned this configuration is headless. I would like to know if this problem happens when you are connecting a monitor. HDMI or Display Port monitor might help.
Does this issue happen with bundled drivers?
Or this is an issue happening with separate drivers for Extensible host driver?
I have not been able to replicate same problem. Would you post step by step information for me to reproduce this issue?