I have a rack with 4 x Dell PowerEdge 2950 servers, and 1 x Dell PowerEdge 6850 (which is in position 2 of 5, counting from the top down).
The top server has been ramping it's fans up lately, causing a noticeable increase in volume. When I've checked the server via Dell's Server Administrator, the server is reporting an ambient temperature of 2-3 degrees more than the other servers, which is why I presume the fans are speeding up.
From what I've seen, the fans are increasing to somewhere between 7,500 and 8,000 RPM when the server is loud.
This server has always been most sensitive to ambient room temperature, but maintaining the room at 24 degrees usually means that I can work in here (no fancy dedicated server rooms here!) without my hands going numb. Lately though I've had to reduce the room temperature to 23 degrees in order to try and placate this server, but it hasn't been completely successful.
Given that these servers are designed to work in a rack, I would be surprised if the fact that this is the top server would make an difference, since the excess heat should be ejected from the back - not allowed to drift upwards.
Any suggestions or comments before I contact Dell ?