Samurai fanless P4?
 

Is it possible to use the Samurai on a Pentium 4 in fanless mode? The TDP is only 61,5 Watts. It's not overclocked and will not be used for gaming. The case has decent airflow. Cables are tucked away nicely and I have 2 120mm casefans.

I'm looking for a cheap replacement for an old system. The Samurai is less then 20 Euros and comes with a 92mm fan that I do need for another case.

Probably not.

The Samurai ZZ is small and has pretty dense fins. Both poor attributes for passive cooling.

You may want to look at a Ninja 2 or Orochi for passive cooling.
If size is a big concern, consider a Ninja Mini with a slow fan.