People do not notice when the fan dies.
When they notice the fried electronics it is too late.
For this reason and for generally prolonging the life of the hardware I prefer fans run at full speed.
I have made photos from my work inside the cramped power supply.
But I am not sure whether it is desirable to post photos.
The work with high voltages is not recommended for unskilled people, which should not be encouraged to do such things.
If you are skilled, you won't need instructions how to connect the fan to 12V anyway.
I did that and noticed that the fan is quite weak for my taste.
It is better than before, when it an airflow was noticeable only barely.
I do not understand.
for the cooling me I multiply the fan and I connect them in 5v or place of the 12v as these possible. for decreased noise.
there is also the laptop fan with the heatsink aluminum and copper, but we must choose the model that will go well with the macintosh
What I mean is this typical situation:
PC with temperature controlled fan. Fan getting old or defective. Turns slower and slower, finally stopping.
User does notice nothing. Only thinks "that is a nice quiet computer!"
PC without cooling runs until overheated electronics finally break down.