Weird stuttering and lags in games graphics under Ventura

Guess, what the reason was... dust!

Yes, over the past years, some dust has gathered in my iMac's vents. The dust lead to less effective cooling, less cooling to higher temperatures and higher temperatures to automatic throttling.

Today, I did some efforts removing the dust bye inserting cleaning fleecing into the ventilation openings moving it around and carefully pulling the out again with the dust. Moreover, I used a vacuum cleaner on the openings with the highest setting available.

Now all my games run much more fluently. I guess, the German proverb is true: The devil is a squirrel.

However, I find a bit problematic that the 2019 iMac is constructed in a way that makes the necessary cleaning a bit hard. You cannot open the casing easily or without loosing the warranty. Consequently, you have to do all the cleaning from outside which is time consuming and less effective.