Hi.

I have been annoyed by Squeak 3.9 making a disturbing high frequency
sounding "noise" on my machine, which I speculate is related to the
graphics card.

Did some research on this and found nothing until I stumbled across
the higherPerformance preference and studied how it was used in the
update loop in the code. (It is on by default in 3.9)

Turns out that if the preference is turned off the noise disappears.
Now working in 3.9 is  a very pleasant experience. Downloaded the
latest version of 3.9 today and our project works just fine.

Many thanks to you are working on 3.9. As mentioned in another thread,
duplicateAllControlAndAltKeys is great, this will make it easier to
use Squeak for teaching (e.g. at our university) because people will
not be irritated by inconsistent shortcut keys.

Best, Micke