[SOLVED] Can you replace the fan on the AMD Spire cooler?

[dhal277]

I have 2 stealth and 1 spire coolers from my previous builds, I know that those coolers are shipped with to different fan variant. The 5 blade (cooler master) version is more silent compared to the 7 blade (AVC) version.

Can I replace the 7 blade fan on the spire with the fan from the stealth? Is there any RPM difference between the fans?

 

[CountMike]

I have 2 stealth and 1 spire coolers from my previous builds, I know that those coolers are shipped with to different fan variant. The 5 blade (cooler master) version is more silent compared to the 7 blade (AVC) version.

Can I replace the 7 blade fan on the spire with the fan from the stealth? Is there any RPM difference between the fans?

Only size matters but if you put fan with lower flow rate instead of higher one you can expect less cooling potential.

 

[Paperdoc]

Obviously size matters - if it won't fit, that is a huge problem. But fan SPEED is the wrong spec to consider.

There are two specs to pay attention to: air flow max (usually in CFM), and pressure max (usually in inches of water). Each of these is a spec given for the fan running at maximum speed, and with virtually no resistance (backpressure) to air flow. In practical use, there always is backpressure flow resistance, especially through the closely-spaced fins of the heatsink that fan is mounted on. But they will never tell you the actual backpressure the fan has to overcome. So, how to use those specs?

If you plot a graph of the actual air flow a fan delivers at maximum speed versus the backpressure it faces due to air flow resistance, it is VERY roughly a straight line - highest air flow at zero backpressure, decreasing to virtually zero airflow at the rated max backpresure. Any flow resistance greater than that, you get essentially no air flow. And of course, air FLOW is how heat gets removed from the fins. (If you plot this graph for a lower fan speed, you just get a similar line of lower air flows against the same backpressure values. This does not matter because the fan SPEED is automatically adjusted by your system to achieve whatever heat removal (air flow) it required.)

If you do this plotting for different fans you get different lines. Some may be almost parallel to others, some may cross others at some middle point. So you need the two specs both for the original fan, and for the proposed replacement. Then you can sketch the two lines. What you want ideally is that the replacement can deliver just as much air flow as the original for almost all of the possible backpressure range. Especially for this application (air flowing through the heatsink) you really need to be confident of good air flow at the higher backpressure end of the line. A small difference does not matter too much IF the original system normally operated well below max fan speed for all of your workload conditions. BUT if you felt the original was running full speed a lot of the time, then you need even more air flow at the higher backpressure end.

Getting the specs can be difficult. Just identifying the fan maker and exact model number may be tricky, but you have the actual fans, so maybe you can read that from their labels. Then finding the specs for each on a maker's web page and be tough for older equipment if the maker never posted that into or maintained an old web page. But see what you can find.