Further Exploring The Intel Tiger Lake Core i7-1165G7 Performance On Ubuntu Linux
At this point there isn't a clear explanation for the difference just that Ubuntu 20.10 is indeed faster than 20.04 with or without the kernel changes. Ubuntu Focal did drop its systemd ondemand service and other udev alterations I was digging through but no clear difference and both 20.04/20.10 on the laptop are defaulting to the Intel P-State powersave mode with Thermald 2.3. In any case for end-users the precise reason doesn't mean all that much as they are unlikely to be heavily modifying their own operating system installation and better off just moving to Ubuntu 20.10 when released in one week's time.
So for seeing the power/performance differences of Ubuntu 20.04.1 LTS vs. 20.10, I ran some single and multi-threaded tests between new, clean installs of Ubuntu 20.04 + Linux 5.9 versus Ubuntu 20.10 with its default software components. The Phoronix Test Suite during testing was also monitoring the CPU core temperature, CPU peak frequency, and CPU power consumption as exposed via Intel's interfaces on Linux.
Indeed going from Ubuntu 20.04 + Linux 5.9 to 20.10 was again showing much uplift for the light workloads with the freshly setup test environments...
But now with this run having the PTS sensor monitoring enabled, we see that on Ubuntu 20.10 the Core i7 1165G7 is indeed reaching 4.7GHz compared to 3.1GHz on Ubuntu 20.04 + Linux 5.9!
Running Ubuntu 20.10 also showed the higher power consumption of the i7-1165G7... Rather than a 6 Watt average for this test, it shot up to 15.8 Watts. The peak also doubled from 17 Watts previously to now 35 Watts. Ubuntu 20.10 is indeed setting something differently with Tiger Lake for enhancing the performance in these light workloads...
But moving from Ubuntu 20.04 to 20.10 with that increased performance also blew out the thermals.... Rather than operating in the mid-40s with a peak at 51 degrees, Ubuntu 20.10 was allowing the laptop to hit in the 90's...
This was also seen similarly on the other single-threaded tests previously performing poorly against Ice Lake... Now on Ubuntu 20.10, the CPU frequencies (and power) are ramping up to where they should be.
But this better performance on Ubuntu 20.10 is also greatly ramping up the operating temperature....