If it's a desktop it's easier to get in and check to see if you need to resit the heatsink, clean the case out for any dust (with anti-static wrist strap and air aerosol - which btw you don't shake before using), check that the ventilation works correctly.

If it's say a local computer shop effort check to see if the fans aren't competing against each other pulling in different directions, but the air flows through the case, not in competing directions.

It could be that the heatsink isn't sat correctly, and that you need to reapply heatsink compound.

If it's a desktop you could potentially fit a tower cooler. The stock coolers from AMD and Intel are frankly quite poor. They are adequate when space is at a premium. If the case has the space a tower cooler can simultaneously run quieter and much more efficiently. Keeping temperatures way down from stock and noise way down.

If it's a laptop you may still be able to clean the internals and check to see if the heat sink compound is appropriately applied- if the design allows. The CPU is often quite compromised in some of these designs. It's far harder to take heat away in the compromised, cramped space of a laptop.
All designs are not equal. Some desktops can be run at turbo mode full throttle (even overclocked)  for their entire lives with no problems, whereas laptop equivalents can  have their performance throttled by necessary thermal management. Specialist high end gaming laptops are another matter. You can get closer to desktop performance for a premium price, and a much thicker laptop.

Both the single- and multi-core performance of Computer2 is better than Computer1.
However, Pianoteq performs much better on Computer1 than Computer2 (many more voices before audio dropouts/clicks/pops).

I notice that in Pianoteq, the 'CPU frequency' is given just as the base CPU clock speed.
Does this mean that Pianoteq only operates at the CPU base clock speed?

Is there a way to realise the additional performance capabilities of Computer2's better processor in spite of the lower base clock speed?

P.S. Computer 1 and Computer 2 both have:
> Windows 10.
> Pianoteq running as a 64-bit VST2 (at 44100Hz sample rate) in Ableton Live 11 with no other plugins.
> Ableton Live 11 running as a 'high' priority task in Task Manager.
> An RME Babyface Pro using the ASIO Fireface audio driver with 128 Sample buffer size (which gives ~ 4ms latency as reported in Ableton).
> 'High performance' power mode set.
> Default BIOS options (e.g. Speed Shift, Speed Step, Hyper Threading, Turbo Boost all on).