Just for example, here is a flight I just tried in a 172, graphics settings on “Low-End”, all online functionality turned off.
You can see the frame stuttering, you can hear the audio cut out a bit, etc.
System Specs:
Intel i7-7700K CPU @ 4.20GHz
24GB RAM
NVIDIA GeForce GTX 1080Ti
Again, MSFS ran without a single issue prior to WU4. Now, it’s unusable.