Wierd fan issue

[AD-15]

hello,

I'm currently using the Silverstone TJ-09 case:



Inside the case, you can see there is an internal fan mount.

Recently, I rebuilt my system to upgrade to core i7. Previously, I had an Akasa Amber fan in there. The cooling was pretty effective, as when I set the fan to run with 12V as opposed to 8V, my GPU temperature would drop by about 5C. However, when I rebuilt the system, I swapped the Amber fan for a Gelid Wing 12 case fan. I thought this would be far superior, as they are quieter (no motor noise), and push a lot more air with a higher static pressure rating 1.95 vs 1.1mmH2O I think).

I expected much better temperature drops, but I found that there is no difference in temperature compared to the Amber fan when it was at 8V. Increasing the voltage across the Gelid fan from around 5V to 12V, I see absolutely no difference in VGA temperatures at all. I've also noticed that the amount of airflow I can feel by putting my hand in front of the fan is very little. With the Amber fan, I could feel considerably more airflow.

This happens only when it is mounted in the fan housing (which has quite a restrictive mesh on one side). When it is on it's own, the airflow is fantastic, much greater than that of the Akasa amber.

So how is it, under restriction, the Gelid airflow falls much more than the Akasa Amber airflow, despite it having a higher CFM and static pressure rating?

[arthurleung]

hello,

I'm currently using the Silverstone TJ-09 case:



Inside the case, you can see there is an internal fan mount.

Recently, I rebuilt my system to upgrade to core i7. Previously, I had an Akasa Amber fan in there. The cooling was pretty effective, as when I set the fan to run with 12V as opposed to 8V, my GPU temperature would drop by about 5C. However, when I rebuilt the system, I swapped the Amber fan for a Gelid Wing 12 case fan. I thought this would be far superior, as they are quieter (no motor noise), and push a lot more air with a higher static pressure rating 1.95 vs 1.1mmH2O I think).

I expected much better temperature drops, but I found that there is no difference in temperature compared to the Amber fan when it was at 8V. Increasing the voltage across the Gelid fan from around 5V to 12V, I see absolutely no difference in VGA temperatures at all. I've also noticed that the amount of airflow I can feel by putting my hand in front of the fan is very little. With the Amber fan, I could feel considerably more airflow.

This happens only when it is mounted in the fan housing (which has quite a restrictive mesh on one side). When it is on it's own, the airflow is fantastic, much greater than that of the Akasa amber.

So how is it, under restriction, the Gelid airflow falls much more than the Akasa Amber airflow, despite it having a higher CFM and static pressure rating?

All the ratings given by manufacturers are only for open air. Once you add in a mesh, the aerodynamics around the blades will certainly change. To achieve a higher CFM and static pressure probably means the fan is optimized for pushing air at certain pressure, and the mesh will affect the intake condition.

I would suggest you either cut the mesh away or see if you can give the fan a bit more clearance (i.e away from the mesh), or just use another fan. There is also a possibility that because the impeller is removable, the back suction will cause the impeller will move closer to the mesh than the Akasa fan and hence further reducing the capability of the fan.

[GoNz0]

looks like that fans designed to run with a lot of obstruction, ie a heatsink in its way, maybe thats why its not much better.

[AD-15]

hello,

Thanks!

I have the fan mounted with silicon grommets. These put the fan a few mm further back towards the mesh. Could this have a significant impact?