While out buying the new camera I purchased a case "exhaust fan", thinking that the whining I was hearing was the front intake fan's bearings going. Having replaced it, I thought to actually turn on the machine with the case open... the whining is coming from the fan mounted on the top of the CPU cooler, which appears to just be a replaceable element bolted onto the top of the heatsink.

In other news, finished work for the day, made dinner and then slept for 5 hours. Thinking I may just go back to bed now and give up on getting any non-work stuff done. If I'm not mistaken, the deadline for PyCon proposal acceptance passed 3 days ago... so guess I'm not speaking this year.