Unidentified clicking sound
I have a clicking sound in my system only at initial power up and diagnostics show nothing wrong or about to fail. Any advice (home built system)
If it is what I think it is, it is relays engaging for your sound card/chip. They use multi-use input/outputs now so that a set of the typical 5 connectors can handle 7.1/5.1/stereo/microphone/line-in etc depending on what is plugged in. To prevent signal noise it is a physical switch that connects these to the proper source.
If not that, then there are the usual suspects. A bad fan bearing can make clicks while it revs up before it starts moving/floating on its due to air flow.
Hard drives unparking and initializing can make brief clicking noises.
Power supplies can make clicking noises, occasionally they have relays as well, but fairly rarely. If it is making clicking noises that can actually be electrical arcing, but you would usually see some horrible signs of failure, or at least an odd smell.
Optical drives that have a disc in them on start up can make strange noises as well.