It seems my antenna for PC issues is clogged at the moment.
I've noticed for a while that my PC was spinning it's fan long and often. I'd also noticed that the response times were a bit slower than usual, part of which I put down to the Windows 10 upgrade I've just done.
Until I came home tonight and found the room boiling (opened the windows) and the machine off.
When I started the machine it took a long time to get going and, eventually, started spinning the fan fast again. So I went and found some diagnostics software which would tell me how hot everything was. It told me my CPU was sitting at around 61C. Now that's not that far off normal ( normal is mid 50's), but still hotter than I would have expected with the fan going so fast.
So I powered it down, lifted the bottom off it and had a look at the fans. A quick spin of the fans showed me that all 3 were moving fine (usual problem is they jam). Putting my hand over the board, though, elicits some seriously hot space over the CPU fan.
I undid the fan and lifted it out. To find the heatsink vent fins almost completely blocked with fluff and gunk. Out with the Vacuum, off with all 3 fans, hovered and blew it totally clean and Voila.
Machine is going like a bat out of hell. Faster than when I first built it clean with W7 nearly 5 years ago. Web pages are startlingly fast and everything is as it should be. God knows how long it's been throttling itself but I'm glad it's back to it's normal self.
When I set out to spend nearly £4,000 I told Mrs S that I wanted a machine I could install the latest operating system on, 5 years down the line and have it run at least as fast as when I bought it.
I've exceeded my expectations and that is really something else. It's not as fast, it's way faster. Windows 10 with good hardware goes like a rocket. OK so I have very fast graphics in it for a "normal" machine, but then I don't play games on it.
It's always useful to get the case off and look for dust every now and then. I should have done this years ago. The fan is almost silent and the whole machine is cool. This might also explain all the network dropouts I've been having. The network adapter is right over the top of the cpu heatsink and was at least 60c.