I also use a T480 as my main laptop and love it. Here are my notes & dotfiles for running Arch Linux: https://github.com/vesche/t480 One big item (which you'll see at the bottom of my install notes) is that intel chips in these thinkpads have a throttling issue. There's a nice python program to fix that, I run it as a systemd service on boot: https://github.com/erpalma/throttled
Is it silent? I've found recent Thinkpads to be a hit and miss in terms of good thermal cooling and fan firmware. Sadly fan speed is not adjustable by the user in the last few generations. I'm also curious about their new AMD offerings.
Fan seems to struggle to dissipate even 25 watts of heat. Sometimes it would be sitting at 50+ degrees C, just idling.
I asked our IT guys if I can repaste it, but they told me it's still on warranty. It might help, but I'll never know I guess.