I have repeated this test with the "Improved Input Response" option enabled and disabled, both producing the same result.
I have also repeated this test with a fresh Launcher install, and several uninstall and reinstall cycles of Minecraft, and are up-to-date on my Windows 10 patches and drivers.
The only constant variable is some of my exported .MCWORLD files that I had archived in another directory. I have been importing them back in to do these tests with. I exported them before the first uninstall/reinstall cycle, though the problem has existed since before that.
Update:
I have since confirmed that the "Improved Input Response" setting does indeed cause issues when enabled. I seem to have stable memory performance now with the setting turned off.
It's a shame that the setting is buggy right now.
It did improve the responsiveness of the game when it wasn't eating a hole through my DIMMs