Fluid dynamic bearings or rifle?

[Carl Patrick]

What is the best type of bearing for a fan that will be on a low profile cpu cooler so it is blowing towards the motherboard?

 

[synphul]

They're somewhat similar. A rifle bearing is similar to a sleeve bearing but lasts longer. Fdb bearings are a bit quieter and tend to last longer than rifle but also tend to cost more. There are variations in between based on brand and you might find one that identifies as a fdb yet is close to a rifle bearing which sort of muddies the definitions.