What 3M and Allied Control promote is 2-phase open bath immersion cooling. Open means there is no pressure build up. Pressure is bad. Things can go wrong. Leaks are inevitable.
Iceotope is single phase and completely different. They could be using mineral oil instead, but don't because for mineral oil they would need to pump it around. They might have some pressure build up, given that they say the Novec expands 6 times more than water. Notice that Iceotope (and oil for that matter) still need heatsinks and stuff. And these heatinks actually can't be using thermal grease, so they have to be removed, cleaned and put there with indium foil or similar things, it would otherwise contaminate the oil or Novec.
http://tv.pionier.net.pl/Default.aspx?id=2786&type=VodMight take a while to load, but shows a lot of details.
