Swaying CPU Fans

Vindi submitted a New Scientist story about a CPU fan that flaps in the breeze. 2cm metal or polyester fan blades, and use less power then a traditional rotary fan. They move less air then the traditional fan, but for laptops, using 99% less power can't hurt. Update Hey its a duplicate from saturday! Guess I shouldn't post while planning my trek to see LotR tomorrow. Go ahead, flame on.

Why not just make cooler running chips?

[Anonymous Coward]

I've been looking into this a lot recently, and there's some pretty (ahem) cool developments on the cpu front recently, with x86 architectures.

Some people point to the VIA C3-800, but if you have real computing needs, steer clear. It runs comparable to a Celeron 400, which is almost, but not quite adequate for general computing. Instead, check out the old reliable suppliers. The shift to .13u means a lot. Frequencies are so high and chips are so powerful that underclocking has become a real option. A good general target for fanless operation is about 12 watts. You can go higher with good case airflow, or lower if you're dealing with troublesome ambient temperatures.

Right now, you can take the Intel Tualatin pIII 1.13GHz (28W), cut the bus speed to around 100MHz, cut the voltage down to about 1.1v and be right in the target range. Of course you won't know exactly w/o experimentation on your cpu, but it *should* be doable. If you're worried about losing efficiency to bus speed, remember that you can compensate by running it on one of the PIII DDR chipsets that are now available (upping effective bus speeds to 200MHz) or waiting until February, when Intel says they'll release a similar part themselves. Additionally, the 512k (vs 256k) cache on the pIII-s will offset lower bus speeds. Just check out the specs of the PIII-M LV models at developer.intel.com and ask how they got to those low wattage numbers with the same core. Since the last fanless G4 was 400MHz and claimed (in its wildest fantasies) to be a supercomputer twice as fast as a pIII, a fanless 800MHz pIII is not insignificant.

Even better, surprise, is AMD. The current mobile palomino runs at 1.1GHz, 1.1v, 25w. This is clearly just an underclock of the current 1.75v desktop XPs. But what it tells you is that the AMD architecture is very open to undervoltage at lower clock speeds.

Now if you consider AMD's forthcoming die shrink, things really look good. Zdnet.de reported (unsourced) that the Athlon 1.73GHz processor would drop from about 75W to 45W after the changeover. Depending on how far you could drop the voltage, you could be looking at a 1-1.2GHz part running at about 10W! Fanless! Now imagine (a beo..no) 2 of these in a well ventilated case, with an MPX board -- 2GHz of dead silent AMD power! Wooo!

Re:The ultimate fan would...

[Anonymous Coward]

contradicts the laws of thermodynamics, unfortunately.

Answer: what is piezoelectric?

[Anonymous Coward]

For those who are unaware, piezoelectric crystals are items that will change shape under the application of an electric field and/or generate a potential difference (i.e. a voltage) when squeezed.
They're used in inkjet printers - they're in ink some cartridge when an electric field is applied to them and they change shape, forcing the ink out of the I also hear the they used them in the ipod for some sort of playlist control mechanism.