[userbinator]

MSN Messenger could do voice and video, in a few tens of MB of RAM, on a single core CPU.

Here's some amusing threads 18-19 years ago when people were complaining that it was using over 20MB:

https://www.neowin.net/forum/topic/273565-msn-messenger-7-at...

https://www.neowin.net/forum/topic/442458-msn-messenger-75-e...