Ensuring consistency and minimal interference during benchmarking? I am attempting to measure the performance of a common piece of software on the current line up of 13” and 16&quot; for the purpose of comparison between models.
Analysing the specs “on paper” may not be ideal since CPUs and memory can perform differently depending on how the software utilizes them, and obvious metrics (clock speeds, cores, memory type and memory GB) don't always correlate with actual performance.
I am working on some simple, reproducible tests to benchmark performance on across MBPs and generate some real, empirical data. They will resemble real-life workflows, and be focussed on heavy compute and heavy memory use. All up they will take under 2 hours per machine, and they don't require Internet.
Question: how should each MBP be prepared before each test is run? There is a strong desire to ensure maximum consistency/accuracy across tests and therefore a fair comparison.
Some things I have considered so far:

WiFi and bluetooth off
Consistent room temperature and (sun) lighting conditions
Close as many unnecessary applications as possible, leaving open only what is necessary for the OS and for the testing software
I am not sure what else, or if there is any established 'best practice'. I am particularly concerned about any 'background' tasks which I may not be aware of which could run during the test and affect the results
Items you've considered are already good! Disabling internet stops lot of stray processes.
You can try Safe mode to do the tests if they don't need the services disabled in that mode. Also consider making a new user account for doing the testing.
https://support.apple.com/HT201262

Safe mode prevents your Mac from loading certain software as it starts up, including login items, system extensions not required by macOS, and fonts not installed by macOS. It also does a basic check of your startup disk, similar to using First Aid in Disk Utility. And it deletes some system caches, including font caches and the kernel cache, which are automatically created again as needed.

That's the closest you can get to a brand new Mac.
Also, if the tests' results use huge storage, its best to delete them after every run since remaining storage also affects VM usage and increases memory pressure.