Here we’ll run through a short comparison of the two Zalman fans. You can see that the ZM-SF3 has more blades and they are thinner with their trademark shark fins on them. They are also slimmer with a smaller curve. The ZM-F3-FDB has deep blades with deep curves. Now, while blade design and impeller design have a big impact on the abilities of a fan, there is no way for me to assess how well these fans perform purely based on that.
Here’re the backs of the fans again, where you can see the pitch in the blades. I think something unique to note here is that the struts of the frame which hold the motor in place are curved with the Airflow on the ZM-SF3; this may actually be a part of the design to help give it a quieter sound profile.
Here we can see both fans have an open-rib design. This is important to note because, as anyone using rubber fan screws or a heat sink with fan clips knows that, if you have ribs in your fan you can sometimes run into compatibility issues with mounting.
We also see that the ZM-F3-FDB gives a diagram of the rotation of the fan and the direction the air flows.
We see here that both fans are open ribbed again. I would like to note that, while it is semi hard to make out, the Zalman ZM-SF3 has a raised surface with the Zalman logo on it. This is a nice aesthetic touch that you will most likely not notice when installed.
Here are both fan cables. As you can see, the bottom cable from the ZM-F3-FDB is not sleeved but comes in a nice Black-Grey-White color scheme. The top cable from the ZM-SF3 is done in a black sleeving that does not let any cable show through.
Both fans also came in at 390mm length for the cables, which is well within the specified 400mm ±10% value given by Zalman. This shows excellent quality control on their part.