No offense, but I'm not sure if it's literally "totally silent", given that you are using a Panaflo that tends to emit motor-friction noise at 5v and that a fan directly mounted on heatsink could cause slight vibration of the heatsink.
The fan isn't quite directly "on" the heatsink, I rolled some tape into a loop and stuck it between the fan motor and heatsink. This way, the fan doesn't directly touch the heatsink, and some of noise vibration is absorbed. But you're right, I made an overstatement. At night, I can easily hear my workstation, and when it's off, I can even hear the server which uses a single fan around 5-7V. I am an optimist for a quieter future
The elastic is basically stretched to the limit of the actual string (with which it's interweaved), so I doubt it can get much looser. In fact, connecting the rubber behind the card was not even required--there was sufficient friction at the holes in the GF4 that the HSF assembly was held firmly in place there. Of course, I may be wrong, but it's certainly worth finding out!
Also slight vibration of HS caused by a fan can lead to slight displacement of HS.
I'm not sure about that, in my case--the vibrations may not be strong enough to overcome the adhesiveness of the AS3.
I second Quokked's suggestion for mounting a fan on a bracket in this regard
I was slow about that bracket idea... of course, the bracket can be bent to put the Panaflo in the same position as now! (Duh
) Having realised this, I must reconsider moving the fan onto a separate bracket.
Reducing the weight load on the elastic is a great idea. However, the packing tape plays a role in directing airflow with my current setup--everything from GPU to memory to misc circuitry ends up getting some airflow. The tape acts like a 80mm-->60mm adapter, in a way. I'll have to weigh the pros/cons of moving the fan.
: I have successfully constructed the hood from Ziploc Freezer, almost identical to yours (PAL8942 + AS3). Using a Panaflo @7V (which is *MUCH* quieter than a 12V Papst 8412NGL I just got...what a waste of money...) I've also modded the Seasonic APFC--I completely sealed the bottom grille (for better forced convection), cut out the entire front-side grille (opposite the fan), and cut out the fan grille and replaced it with a "real" wire-made fan grille. Instead of the Adda, I put in another 5V Panaflo:
So, 3 fans total, 7V, 5V, and 5V. Inevitably CPU temps are greater than w/Intel HSF... at 2550MHz I get arithmetic errors in BurnP6 as soon as the CPU reaches 65C. However, moving down to 2517 fixed that, and temps safely stabilized at 66C (and 58C after real-life benches like UT2003). Ultimately, I'll probably move down to 2500MHz while AS3 settles and makes it even cooler.
More details to follow, and your feedback is welcome. Here is my case view (just added:)