I think that they are all brushless. The delta one says so. What I was hinting to was that there are at least 4 different versions of the fan and they seem to have been used quite randomly except for the delta which I expect to be noisier and higher speed with it's 1.1Amp rating and was only used on the G3. My 65W unit surprisingly comes with the lowest power rating of 0.5Amp so it must be quite slow. I have a 600 G5 (35W) which came with the AVC 0.8Amp. I am trying to acquire a delta unit to see if it can improve cooling. In the meantime I just swapped the fans between my units.