I managed to get this permanently sorted for myself, sharing the tips so everyone else can avoid the same user errors I did. I am running a Surface Book 2, FYI.
Firstly, it does not like being made to run high performance in clamshell mode, as heat dissipation is not optimal. This causes the system the throttle the CPU, in my case down to 0.8 gHz… meaning there was no longer enough processing power for real-time processing. Cue the emergence of clicks and pops. This is exacerbated by moving the power slider to “best performance”, which you need to. When not in best performance mode, the CPU frequency is throttled dynamically to conserve power. As it throttles up and down to meet shifting demands, it hits the point where real-time output suffers, creating the odd click and pop.
Also, my CPU has 4 physical cores and 8 logical ones. Cantabile and Reaper identified this as 8 cores, and defaulted to running multi-threaded with 8 cores. However, because real-time processing is critical for audio, this actually resulted in more clicks and pops. Manually setting this to the number of physical cores (in my case 4), solved the problem.
In summary:
Clicks and pops were related to CPU throttling down due to heat, CPU throttling down due to power conservation, and the DAW trying to make use of all logical cores instead of all physical cores. Making sure your mobile system is sufficiently ventilated, your power setting is on “best performance”, and your number of cores is the same as your physical number fixed this for me.
Previously, I was unable to run a single heavy load patch (drive pedal, compression pedal, 2 amps, 2 2048 IRs, stereo delay, reverb, chorus) without clicks and pops. Once I had all that sorted out, I managed to get 8 instances of that heavy-duty patch running at a buffer of 96 with 2 ms latency… Now I’m satisfied (also, embarrassed of my user error and pleased with having resolved it).
Hope this helps anyone else who’s run into problems.