Just upgraded from my old i5-4430 to the new 3700x. I'm very happy for the performance upgrade but there are a couple issues. I had to install Ubuntu using the netboot image because of the RDRAND bug affecting systemd. Systemd has already been patched with a workaround but the old one is hardcoded in the standard Ubuntu ISO. As usual the drivers for new hardware are lacking on Linux, as far as I know temperatures and fan controls are off the table until Linux 5.4.