The thinkpad p1 gen4 is a good laptop, but the fans run SO loud under system load (and especially when charging) that I almost had to return it. If this were a machine I was using on battery frequently, I wouldn't be able to use it due to the intensity of the fans. Luckily, I sidestepped the issue by throttling the maximum processor speed to 99% instead of 100% in Windows: this apparently is enough to prevent the machine from lurching into blastoff mode. I can still use it for fairly resource-intensive audio production and editing without noticeable performance loss.