The x3650 M3, or at least the one I've got, has 3 fan modules each with 2 couter-rotating fans. I removed those, put some regular heatsinks on the Xeon CPUs.
I used Intel STS200C heatsink/fan units - these are designed for socket 2011 so I had to modify them... the mounting dimenions are basically the same BUT the screws are thicker and thus don't screw into the M3 mounting points.
This was probably the worst part of the mod - I had to remove the OEM CPU heatsink retainers from the server, remove the screws, remove the screws from the STS200C, drill out the STS200C holes to fit the bigger pins from the OEM mounts and then attach the OEM mounts to the STS200C.
Once that was done, I wired the fans up to existing fan headers. Here's the pinout (I couldn't find this anywhere on the net - I hope it helps someone)
To get rid of the IMM fan faults I discovered that I needed the tach wires connected to tach A and B for fan headers 1,2,4,5,6.
Looking at the front on the server it goes:
Right to left
Zone 1, fan header 1 then 2
Zone 2, fan header 3 then 4
Zone 3, fan header 5 then 6
Next problem was an over temp on IOH - the I/O Hub which is behind the CPU in Zone 1. Obviously the OEM fan unit cools this better.
To solve this problem I removed the heatsink, put some thermal paste and zip tied a fan to it, connected with PWM to one of the fan headers. Maybe I'll come back and fix this up a bit later but it seems to work OK.
The overall result - the server is WAY quieter. Before mods I could put it in a room, close the door and still hear it. Now it sounds pretty much like a normal PC. I've got 2 SAS 10k drives in there and the seeking noise they make is louder than the fans ....
As for temperatures, who knows, the IMM doesn't give CPU/IOH temps, so until some over temp warnings show up or my CPUs are fried, life is good :-)
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