CM has a horrible background almost as bad as OCZ was when it comes to their power supplies, looks excellent on paper, yet in the real world tend to fall markedly short of "what is on the sticker" there is a reason why they are at a budget price point afterall. I am quite sure when you have the PSU pushing its max wattage say 600w the fan would be working overtime to keep in that 40c zone, or there will be problems....
On another note, I really wish PSU, GPU makers would make the fans able to be super easy to remove to maintain them and/or replace them as needed without having to take a boat load of screws off or fight with the shroud. XFX had the right idea with 2 "clips" for some of the RX 400-500 offerings, but, not the right idea of excessive price premium...
It should be kind of a mandatory thing IMO, really would not be hard for AMD/Nvidia to have that as a base specification that needs to be adhered to AND again IMO stop using those terrible hard to find "blowers" am sure one could just as easily use an off the shelf 38mm thick 92-120mm case fan on an incline to have the same "pressure" as "reference" design, would be by far easier to keep cleaner for longer, likely be much quieter, easier to replace once it "fails" which many tend to do...
They (all computer makers/producers) really really need to BY DEFAULT be able to take the fans out to keep them clean, they could easily lock the rest of the PSU or GPU to prevent taking things off or whatever, but no reason why any maker makes the cooling fans near impossible to replace, Sony Microsoft am looking at you especially, custom fans locked in a box that you have to break the warranty void if removed sticker to replace the fan OR have to send it into them to replace, would be far better for them AND the consumer to be able to clean/replace the fans if they were readily accessible without monkeying with anything else....dummies ^.^