My laptop has an internal modem I rarely use. Currently it's one of those moments. It is a so-called winmodem that is no real modem, but just a sound device with a splittet driver: An in-kernel alsa one (free) and a proprietary daemon emulating a modem.
I wondered why some tasks that have nothing to do with network were slow as hell. Now, I knew that it just emulates, but I never thought of that:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
30458 root RT -6 4384 4384 3588 S 17.3 0.9 8:37.33 slmodemd