While looking for a fix, I found this old post where Fiery says:
"It seems on some configurations reading EC (Embedded Controller) registers cause high DPC latency. The only "solution" we've found so far is to disable EC readout by disabling the following options on the page AIDA64 / main menu / File / Preferences / Stability:
Embedded Controller (EC) support
Embedded Controller (EC) bank switching
After altering those options, make sure to restart AIDA64 to apply the changes. However, by disabling those, you will lose a set of sensor readings, e.g. PCH temperature, T_Sensor1 temperature, WATER_IN temperature, WATER_OUT temperature, Water Pump fan, Water Flow fan, VCC Sustain voltage, CPU PLL voltage, VCCMP voltage."
So, I disabled Embedded Controller (EC) support and the stutter is gone. Also, Aida's CPU usage went from 10-15% to 2-5%
Temp sensors for PHC, VRM and an external sensor I have connected to the MB disappeared, but at least I have everything else and no stutter... Till there is a better fix, it will have to do...