Pushing a CPU to Heat Death, Intentionally 291
sdougal writes "This site is showing a Pico-ITX board running Ubuntu with no cooling whatsoever. They even let the public guess how long it would last: 'Last week thousands of you placed bets on how long the new Pico-ITX board from VIA, the VIA EPIA PX5000EG, can last without any cooling whatsoever. An ARTiGO Builder Kit was offered as the grand prize. Yesterday afternoon the voting stopped and the Naked Pico Challenge started in earnest. We simply loaded up Ubuntu 8.04, set it to work playing an mpeg-4 video and then removed the heatsink, leaving the CPU and VX700 chipset bare to the world. We recorded the event here in this video and set up a live video stream so you punters can keep a watchful eye on the PX5000EG as it works away.'"
Re:Why should it even crash.. (Score:5, Informative)
Re:Open != better cooling (Score:3, Informative)
This isn't readily apparent in most modern equipment because hot components have their own active cooling, and the ambient air is cooler outside the case.
However, if I turn up my 3-speed 120mm case fans to Max, as opposed to Min, my CPU temperature will drop below what I am able to achieve outside.
But that is only possible when the wiring has been carefully managed to avoid heat traps.
Re:AMDs don't need CPU fans, either (Score:5, Informative)
Intel had recently introduced an overheat sensor into their CPUs. They still have them, I think. There's basically a thermal probe included in the CPU packaging, and if the temperature goes over a certain critical level, the CPU starts throttling itself down, until the temperature goes down to a safer level.
Tom's Hardware (probably being paid by Intel...) did a video experiment on this. They got an Intel (early P4, IIRC) and a then-current-gen Athlon, started them both playing Quake 3, then removed the HSF.
The Intel chip promptly throttled itself down to 400MHz or so, and kept running the game (rather slowly). The Athlon crashed, hit something like 200-300 degrees C, and burned a little hole in the motherboard.
After that little stunt, AMD started building overheat sensors into their CPUs quite fast.
I saw this in action on one of my own machines, a Shuttle SN62K, a couple of years back. That machine has a known issue with the motherboard fan headers dying after about a year of use. It's also a very quiet system. I was using a 2.4GHz Celeron in it at the time. The fan header died and the fan (only fan in the machine, if you know Shuttles) stopped working. The CPU throttled itself down to 800MHz and kept right on going, for two weeks, before I actually noticed.
Re:AMDs don't need CPU fans, either (Score:2, Informative)
Really? The CPU got so hot it went into a liquid or gaseous form? (You can't scald yourself on something solid.)
Re:How about (Score:4, Informative)
Will what melt, the CPU, the server, the building, or the polar ice caps?
Shit, my ice cream cone just melted...
Re:Ehh, it's been done before (Score:3, Informative)
Re:Ehh, it's been done before (Score:3, Informative)
Re:The rule of thumb is.... (Score:5, Informative)
However, CONDUCTIVE heat transfer (getting the heat to go from the "hot" end of the heat sink to the tip of the fin) is directly proportional to surface area. This means that, were you to use a single sheet of aluminum foil as a "fin" on your heatsink, you would not be able to get the heat to actually travel effectively to the tip of the fin where it could be removed via convection. Thus you'd wind up with a very hot "hot" end of the heatsink (near the chip, which does you no good), and a cool "cold" end of the fin (which is worthless, as convective heat transfer is proportional to the difference between the surface temp and the air temp). If you were to instead use a thick sheet of aluminum as your "fin", that would allow the heat to easily travel from the "hot" end to the tip of the fin, where the air could take it away.
However, you can get the best of both worlds by using multiple thinly-sliced sheets of aluminum. Same cross-sectional area as the thick slice (for good conduction), and maximum surface area (for convection). Which is exactly what most heatsinks look like.
Re:Ehh, it's been done before (Score:3, Informative)
The average entry-level Intel-based desktops I sell, they eat 50 watts. They don't run fanless, but they are effectively noiseless beyond a foot. This is for a 2ghz Core-2 with 2gb ram and a SATA hard drive. Considering the Intel puts out at least twice as much performance as the Via, plus the second core.
I have yet to put them to work as servers and media centers, mainly because I don't have the time and my old gear still works well (XBMC + a weak old AMD X2). Still, I see very few advantages for the Via when compared with today's uncrippled desktops. Five years ago, sure, Via was unique, but they've been resting on their laurels for too long.
Re:Ehh, it's been done before (Score:1, Informative)
Re:AMDs don't need CPU fans, either (Score:3, Informative)
Last week the fan on my laptop failed (Intel Celeron). It took me an embarrassingly long time to figure out why the thing was suddenly running so slow (It runs quiet anyway). But it still ran. It ended up running for a day and half straight, under load, with no fan. Replaced the fan, all is good.
Re:Done, accidently, before (Score:4, Informative)
Re:And mine survived - The article's CPU might, to (Score:3, Informative)
Anything older than that P3 would have cooked. That P3 went into a frozen state to save itself. The P4 and newer underclock themselves until they're running cool enough, and freeze if that's still not cool enough.
Re:Ehh, it's been done before (Score:2, Informative)
Probably for smoothing(filtering) the input voltage. A radio will easily function without these, especially if run off battery and not mains. On mains you'd get a nasty hum.
Re:Ehh, it's been done before (Score:4, Informative)
Obligatory (Score:2, Informative)