How to reduce the noise of a full tower server?

Question

Noise suppression

Almost for nothing, I got an elderly server in the form of a full tower cad-station. It has two old Xeon E5405, an Asus DSEB-DG motherboard, a bunch of RAM with 8x2Gb chips, a case with a hefty basket and half a dozen hard drives, a 700-watt power supply. Everything is fine and the performance suits me, only this design makes noise, although not like a rack server, but on the very verge of comfort. And since this is all such a cad-station, and not a rack-mount server, it was still originally intended to work with people, and therefore, it seems to me, it should be possible to wean him to portray Carlson at idle.
I guess several ways:
-- soft cooler speed controller under Ubuntu 12.04, is there such in nature?
-- connection of coolers through loops with resistors, or to 5 volts
-- buying a simple reobas, instead of the item above
-- replacing coolers with less noisy ones, picking and replacing grids
-- everything is higher in the aggregate
. Can someone advise specific available models (in Moscow, preferably in Citylink) and how to connect / control them, based on their own experience? In order not to buy a pig in a poke: "Pour me a hundred grams of these for a sample." Moreover, fans for the old xeon socket are no longer on sale, and not all coolers will fit into a limited space on the motherboard, there is no gap at all between the boxed processor heatsinks.
The ambush is also in the fact that you don’t want to invest a lot of money in a free server, a maximum of a hundred bucks ...

Answer 1

Why Variable Speed? In moments when quiet work will be missed, put on construction headphones and cool?
And you need to decide whether you got a server or a cad station, since the servers do not imply silent operation, because they stand where they don’t give a damn about it.
Judging by my experience, I can say that miracles do not happen.
At choice temperature - water - unloading of the case.
If you choose low noise fans - these are almost always low speed fans (large size, low RPM) which will cause the temperature to rise if left as is.
If you choose low-speed ones and unload the case a little, throw out (or throw out and replace) the hdd, leaving only 2 in the end (if you need a raid).
To see what temperature the processor is under load, it may be possible to make passive cooling only with case fans (look at how cooling is done in Dell).
As for the fans, everything is standard here, Coolermaster, thermaltake, etc., etc.
They are selected according to the size and the noise declared in the technical characteristics.

Answer 2

By replacing the fans with slower ones, you will deprive the server of normal cooling.
Now it has become fashionable to hide equipment in cabinets with active noise suppression technology and put it all right in the office. There is even a video with testing. True, the price tag is horsey, but according to calculations, it seems to be more profitable than building a server room.