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Watercooling Drifting Mainstream
pacc writes "With Prescott said to dissipate 103 W and the dual Apple G5 playing in the same league, air cooling seems less than sensible.
Nikkei Electronics has an article about watercoolers getting standardized by Hitachi. A technology pioneered by a NEC desktop last May."
The 103W figure for the Prescott 3.6Ghz is actually the Thermal Design Power. This is the amount of power the processor is expected to use during "normal" operation. A P4-C 3.0Ghz with HyperThreading has a TDP of about 80W, with an actual maximum power usage of 104W. Assuming a similar scale, a Prescott 3.6Ghz can be expected to dissipate around 130W. It's this maximum figure that really matters, since I don't think most people want their processor to throttle during gaming or whenever they are driving their CPU hard.
Yes. It's much like comparing a 486 to a P4 3GHz. The water cooling is much quieter, runs much cooler, and allows for creater control over temperature. If done right, there is no risk of frying your system, unless you cut the hoses or something, but even that can be protected from. Plus, if you have any kind of case window and lighting, you can injust florecent(sic) coloring into the water system and use clear tubes, giving a very cool light effect.
Space for rent, inquire within
Overclockers use Peltiers often. The problem is, that while a Peltier gets one side VERY cold, the other side gets VERY hot. Cooling this side requires you to either attach it to a waterblock in a watercooling system (which is what you were trying to fix in the first place) or put a big fan on it with a heatsink (which is LOUD and innefficent). The fact is, a Peliter would only make things WORSE as far as "cooling things quietly" goes.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
In the article it mentions:
The water cooling technology can significantly reduce the noise level. Equipped with a microprocessor whose heat dissipation is measured to reach 75W, the NEC desktop PC can suppress noise level to 33dB (A) owing to a water cooling module inside it. As its level was measured to be 43dB (A) with an air cooling system, the noise actually has gone down to one-tenth.
Do they not realize that the decible is measured on a logrithmic scale?
http://www.water-cooling.com/
Water cooling obliterates air cooling. I used to run a thermaltake slk800 with a 120mm fan wired to it with an adapter. It pushed 80cfm and kept my seriously overclocked athlon tbred 1700+ running at 38c at idle, and never over 48c at full load. With water, I haven't seen 40c yet under extreme load. I idle at 33c. And I have a crappy thrown together setup right now. There are guys that have never seen 27c.
For every annoying gentoo user, are three even more annoying anti-gentoo crybabies. Take Yosh from #Gimp for example.
Tom's Hardware Guide - search "water"
Learn more, it is facinating. Look around the old articles on HardOCP and Overclockers.com and you can find out a ton. Just search google! Also, if you look at like the HardOCP forums under cooling, you can find tons of pics of people's Watercooled PCs.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
The benefit of water comes from several aspects: 1) High thermal capacity - as you said, acts like an energy buffer. 2) Higher thermal conductivity than air - allows heat energy to be transferred faster. 3) Allows radiator (YES! you need a way of dissipating heat) to be located remotely from the CPU. This means you can have a much larger radiator, with far more surface area and airflow than would be possible with a CPU mounted heatsink. Remember, water is just a transport mechanism - ultimately the heat has to escape to the air. If you build the radiator large enough, the temps will be lower than you could practicalally achieve with standard air cooling.
Since when is 43 watts @ 1.8ghz, (I don't think they ever released the 2Ghz G5's power dissipation number, did they?) in the same league as 103watts?
While it puts out a bit more heat than the G3s and G4s mac users are used to, the G5 is still nowhere near as bad as prescott.
The prescott puts out more than doubble the heat.
"The worst tyrannies were the ones where a governance required its own logic on every embedded node." - Vernor Vinge
Overclockers.com maintains a nice database of the relative performance of various air and watercooling systems on a variety of platforms: The Heatsink and Watercooling Roundup.
Intel Prescott, the chip that's slated to set power dissipation records for mainstream CPUs, uses a new .09 micron process. Apparently Intel is seeing fewer benefits than they expected.
The heat coils have a lot more surface area, and are located outside of the fridge. Most fridges simply use convection to cool the coils, and thus no fans (I have seen some fridges that do use a fan though). The compressor generally makes much less noise than the computer's fans. Fridges contain a lot of insulation and are air-tight, and thus noise cannot get out, so chances are you could put a ton of fans inside the thing and not hear them. This is the theory.
But a standard little dorm fridge will not work. They are not very powerful units, only capable of moving as little as 100 BTU/hr of heat out. (Most window air conditioners can pull out 5000 BTU/hr or more). 100BTU/hr is about 100,000J/hr or about 30W (30J/s). Now this is fine for cooling your pop and salsa and holding it cool - but most computers pump out considerably more heat, the new Intel processor all by itself puts out 3 times as much heat! What will happen if you try this mod is that the poor fridge is not going to be capable of pulling out that much heat and the computer is going to roast itself in the insulated fridge. Not good.
A regular full sized fridge can pull out about 650BTU/hr, or about 190W of heat. This is closer to workable, but considering 350W+ power supplies are the norm now, even then I think the computer will slowly roast itself in the fridge anyway. And you also have the problem of wear on the compressor which will be running almost continously, and will probably burn out quickly. Not to mention the energy use of running a fridge like that.
I think the only solution for a super-cool rig will be to either get something like an aquarium chiller, that can take out something around 1600 BTU/hr and is already setup to chill liquids (perfect for water cooling I guess), or work with trying to convert a window AC unit as a computer cooler. You could also try full sized freezers, especially the top-loading ones. I don't know how powerful they are, but they are probably more powerful than your standard fridge.
...is at least partially liquid cooled. Apple has been doing this since the G3 Powerbooks. So it only makes sense to use the technology on the G5's...
Actually with Peltiers your risk can be larger due to condensation. Peltiers can cool the chip down way below ambient temperature, so water can collect. This is why serious applications of Peltier coolers include rubber seals and other devices to manage the water problem.
A passive water cooling system won't lower the temperature below ambient, so condensation is not an issue..the water stays inside the tubing, not dripping from the bottom of your motherboard. (Now active water cooling is a different story).
A few keen hobbyists/overclockers have done it - often using mineral oil.
In reality, it's not practical, or necessary. In fact, it's just plain messy. Most components work fine with air cooling. It's just a few hot spots (CPU, GPU, HDD etc) that can benefit.
The thing to remember that there is a practical upper limit to conventional cooling solutions. Let's assume for a minute that some exotic water cooling rig could dissipate 210W from a system (including video card, power supply, etc). This heat would still need to be transferred out of the room/house. It is easy for datacenters or specially prepared rooms to dissipate excess heat but in your stereotypical house with central air this is going to be a serious problem.
It would be interesting to see if something using a endothermic reaction or maybe a condensor could be made practical as a supplement or replacement to a more conventional cooling system. This would obviate the need to dump the heat.
To join in with the peanut gallery: it's not a radiator, it's a heater core. OTOH, it's larger than the radiator on many motorcycles, is constructed the same way, and does a similar job.
The guy did some great work, but the English wheel to make a simple curve was big time overkill. English wheels are used to make compound curves, usually.
As far as the 'last' great love affair with speed and power being the automobile, America's love for speedy and powerful autos is as strong as it ever was. Fast computers are barely a glint in the eye for the average person. Hell, even most geeks who really make it buy rather nice cars (ask John Romero). And the lowly Dodge Neon is quicker than most average Dodge musclecars of the late 60's, with superior economy and handling. Only seriously high end race only cars back in the day would stand a chance at hanging with something as relatively mundane as a Subaru WRX. Maybe a Yenko or other tuner car could beat them, but then you have to let me mention tuner Corvette's and Mercury sedans. Trust me, *this* is the golden age of the American auto, despite the prevalence of SUVs and trucks (which are quicker, safer, more fuel efficient, more powerful, and more durable than their brethern 'back in the day'.)
While I'm wound up, let me tell you why emacs rulez, and vi is teh suxx0r...
Jesus was all right but his disciples were thick and ordinary. -John Lennon
And about the only way to do this without sacrificing clockrate is by going to a smaller fabrication process.
Sorry, that's commonly believed, but wrong. There are lots of ways to reduce power consumption. Reducing gate widths (0.25um -> 0.13um -> 90nm) is commonly touted as a good way to reduce power, but in most cases that's more marketing pitch than reality.
First, there are two types of chip power to worry about (1) leakage, which happens all the time, just by being on, and which used to be always much much lower than (2) the switching power, or maximum dissipation when as many transistors as possible can switch at once (which, BTW, can never be all of them, and it's really, really hard to find the stimulus that makes maximum power happen. So, esitmates like the ones in the article for peak power are often made assuming a somewhat-arbitrary switching factor that may be low or high).
As gate sizes shrink, the effective capacitance of the gate shrinks, and voltage can be lowered (to a point). Capacitance varies with gate area and inversely with distance between "plates" of the gate (C = k*A / d). Reducing the gate width (space between the plates) actually increases capacitance, and this itself would increase power. But, you're also able to reduce the gate area (though not as much, but in 2-dimensions, so shrinking gates is usually a reduction in C). Most importantly, you can decrease voltage, since power varies with the square of voltage, this has much more impact on power than reducing gate capacitance (size). When we went from 0.25um (3.3V)to 0.13um (1.5V), we got a nice fat 1.8V drop in voltage. But 0.13um is 1.5V too, or 1.3V at best, and I've never heard of a 90nm (0.09um) process under 1.1V. The V isn't dropping as fast any more because the noise margins are getting too small.
Since p(switching) = 1/2*F*C*V^2 (F = clock freqyency, C = capacitance, and V = max voltage, lowering C (and moreso V which we can reduce some, but not much below 1.0V so far) will lower power a bit. Linearly with C. But unless we can reduce V, reducing C much more won't help a lot because we have more total C's (transistor gates) on the die, because they are smaller we can fit more.
But now, at 0.13um, and more at 90nm, it's not the switching power, but the leakage (always there) power that's getting worrisome. It used to be 1/20th of switching power or less, but now the gates are so small current of the same order of magnitude (almost) of switching leaks all the time.
So, the more you shrink, the more you have constant power, which is harder to deal with since you can't throttle it, and it's always cranking out. Worse yet, the more you shrink, the more gates you can fit on one tiny little die (the feasible mfg'able die size stays around 17-18mm max regardless of gate size once the process matures a bit, but bigger dice have ridiculous failure rates and thus silly high prices). And the gates shrink in 2 dimensions (L and W), so you get a squaring increase of the toal gate count, and only a linear decrease with C. Shrinking gates to save power doesn't work.
So, if we can't keep shrinking to save power, how can we? Lot's of ways. There are dozens of EDA companies with power-minded RTL coding, synthesis, and even place and route tools ready to help you reduce your power if you have a few $100k/seat/year. Or, you could use a SSC (Spread-spectrum Clock, where each clock edge is off by a bit to reduce power, but it slows down the max clock rate a bit too, of course). You can also try to use beneficial clock skew to reduce power after timing closure, or gate the hell out of all the clocks and only enable what you need (a la mobile chips). Or switch to asynchronous, or self-clocked design (every thing has it's own clock, which sends a clock to the next thing, etc. -- it's HARD to design!). Anyway you look at it, it's a hard problem. And people who
everything in moderation
Pluggable liquid-cooled rack-mounted modules are not the way to go. Ask anyone who had a liquid-cooled IBM mainframe. It used to be said of the IBM 370/168 that it needed "six plumbers and a CE (customer engineer)."
I'm not an OCer but I wonder about this...what about the heat generated by hard drives? Hard drives generate a huge amount of heat. If you cooled the hard drive using a water cooling setup, how much could you OC the CPU without water cooling it since the ambient temp in the case would have been reduced by some large amount.
If you water cool both, you could probably run the computer with only the evaporator fan.