How bad were things for you prior to the firmware update that fixed RPi 4 temp? I tested on those, but not for performance, just for temperature under max CPU

How bad were things for you prior to the firmware update that fixed RPi 4 temp? I tested on those, but not for performance, just for temperature under max CPU load. I remember getting the impression that a Pi 4 working under that kind of load, and throttling pretty constantly, would probably suffer roughly a 15% performance degradation but I didn't test that assumption much. I had a funny moment during testing of comparing an 8GB and 4GB Pi 4, each with different revisions of the firmware, and wondering how the hell the temperatures could be so different.