Gee... I wonder why?

[EricKei]

TY for reminding me to actually finish my post x.x

My best guess -- Properly-cooled electronics can be pushed harder/work faster. Many computers, in particular, will throttle down or simply shut down on their own if they get above a certain temperature. It could also be that the sheer volume of dust was interfering with something mechanical such as the hard drive, I suppose (tho they're supposed to be closed systems)

[Chromatix]

I figured it was something like that. I'm still trying to figure out why the computer in question sped up, though.

It is very simple. When the heatsink is clogged up, it can't remove heat from the CPU (etc.) as well as usual. That means the CPU gets hotter. Most modern CPUs have a feature that reduces the clock speed and voltage when they overheat, mostly to prevent damage.

If you regularly see a noticeable performance improvement after cleaning your machine, then you should clean it more often - because the obvious corollary is that it is getting dirty enough to start overheating.

[lordlundar]

It is very simple. When the heatsink is clogged up, it can't remove heat from the CPU (etc.) as well as usual. That means the CPU gets hotter. Most modern CPUs have a feature that reduces the clock speed and voltage when they overheat, mostly to prevent damage.

Yup, because when a CPU goes, it's not pretty. It can be pretty loud though.

(seriously, I saw a video of a CPU at full throttle when the sink was removed. There was a loud bang and a CPU shaped hole in the board and the thin stand the motherboard was resting on. And that video predates multi core units)

[EricKei]

LL -- While this may longer be the case, it was my understanding that DualCore (and higher)-type CPUs run much cooler than older CPU types. One "preview" I read when they were first coming out (read: still ALL overpriced) compared the temps for no cooling vs stock fans vs super-duper-complex cooling systems, as a foundation for potential overclocking experiments. IIRC, the early DC's were as much as 10C cooler than an equivalent (roughly the same speed) preceding-gen chip even with no cooling whatsoever (running at their default speeds), and the guys in their lab were able to maintain a stable overclock in the 50% range or better using generic/stock cooling, without raising temps into dangerous territory. 5 years earlier, and a stable 20% OC would have been impressive, and might very well require uber-coooling setups.

[lordlundar]

Well, when the result is the CPU acting like a shaped charge about 1 second after the sink was removed, the difference of a few degrees with the sink on it isn't going to matter much.

[Apallo]

Well, when the result is the CPU acting like a shaped charge about 1 second after the sink was removed, the difference of a few degrees with the sink on it isn't going to matter much.

I remember there being a couple/3 videos of a guy taking the heat sink off of the early AMD Athalons while they were under a load. It was amazing that the little core could blow a quarter sized hole right through the bottom of the motherboard. He did the same thing to an intel system and it slowed to a crawl, but didn't explode.

[Chromatix]

The thermal load of CPU designs goes up and down over time, and varies considerably between models in the same generation. However, *most* ordinary consumer CPUs today consume noticeably less power than the last models of the Pentium 4, which was the point where Intel discovered what's known as the "power wall". They've paid a lot more attention to efficiency rather than raw clock speed since then, but it is still advisable to fit a really good heatsink to a high-end CPU. Heatsink design has also evolved and improved since then.

However, while the P4 pioneered thermal protection through throttling, all modern CPUs have that feature to at least some degree. I think the extreme case of no heatsink at all is still problematic, but the system can react more reliably to a heatsink without a working fan or with severe clogging.

[IT Grunt]

Back in the day when I worked in the IT department of a bank, I got called to a branch one day to deal with a teller machine that wouldn't boot up. If I recall correctly the machines where made by Culverin and were 'dual' machines, IE each machine had two monitors and keyboards connected to run two teller windows from one box. So, one going down meant taking out two windows when there's usually four, so it needed fixed. Grabbing up a spare I'd resurrected, I went down...

When I got there, it wouldn't boot up as described. It would power up (or at least try), but the power light just kept flashing on and off, and it made a faint 'tick tick tick tick' sound. The funny part was, the tellers actually thought it might have been a bomb. I assured them that it wasn't. We're just dealing with a broken machine.

Opening it up... well... it showed the effects of being under a teller window for a couple of years at least. Dust a half inch thick, the only way you could tell what was what was from vague shapes, and the fan was caked with it. It turned out the power supply was making the ticking sound, basically switching on and off rapidly when you turned it on. Though given how much dust was caked in it, I'm surprised it didn't go off with a bang.

[SongsOfDragons]

this is why I keep at least one can of compressed air about. Once a year, at a minimum, open the computer case, remove the dust w/ the compressed air. Amazingly, it tends to speed up the computer. That, and I noticed the fans didn't need to work as hard afterwards...

It works wonders for my laptop - when I can bring it to our local computer whiz. I just don't have the guts to try and take off the back for fear of breaking stuff.

[sstabeler]

OK, with talk of CPUs acting like shaped charges, and with at least one of my computers having had a power supply burn out ( I assume so, anyway- the computer suddenly shut down, and a small of burning came from the PS...) I am definitely cleaning my computer more often. Maybe this is why I can never keep a computer working more than 3 or 4 years...

[lordlundar]

The exploding CPU is if there's no heat dissipation in short order. You do have to try to make one go boom. Worst case scenario is that something will just go "nope, can't deal with it anymore" and stop working, causing a cascade effect with several components burning out. You'll get the mysterious blue smoke long before you get the loud bang.

Still, it's a good idea to clean a machine on a regular basis anyways. I usually do every 6 months with my family's air compressor. Sounds a little funny afterwards for a couple of days (a fan goes just ever slightly off balance but readjusts itself) and it keeps it running smoothly.

[Chromatix]

The most likely components to fail in an overheating PSU are:

1) The main power transistors or diodes, which are attached to heatsinks. If one of these blows, the PSU will usually not work at all, and will probably emit loud noises, sparks, and/or magic smoke.

2) Electrolytic capacitors, which tend to dry out. They do that anyway over a period of a decade or three (depending on quality), but they do it many times faster if overheated. Most PSUs have several large ones installed.

The "tick-tick-tick" sound suggests to me that capacitors have failed. The PSU is gathering enough stored power to switch on, but is then unable to sustain steady power conversion between peaks in the 50 or 60 Hz main supply, at which point the undervoltage/overload protection circuits automatically switch everything off.

Check the POS that is still working, as that is probably clogged up with dust as well.

[sstabeler]

The exploding CPU is if there's no heat dissipation in short order. You do have to try to make one go boom. Worst case scenario is that something will just go "nope, can't deal with it anymore" and stop working, causing a cascade effect with several components burning out. You'll get the mysterious blue smoke long before you get the loud bang.

I'm sorry but I have a nasty knack for things to go wrong in unusual ways. (for example, i once discovered my computer chair needed replacement because the piston suddenly broke free, sending the rod into the floor, the chair up into the air, and me to the floor.) I'll just keep a wary eye on the internal temperature gauge I have on my PC.

[AdamAnt316]

I found out what that dust in the laptop was....get ready for it.....it's bird dander. The owner has a boatload of birds apparently.

I can completely understand the bird dander thing. We used to have a pet cockatiel, and every time he ruffled his feathers, you could see a visible cloud of 'dust' fly off. It coated the CRT TV near his cage, and generally got everywhere. My brother kept his laptop not too far from the birdcage, and I wouldn't be surprised if that's what eventually killed it.