I’m getting a lot of emails, that stripped to their core, say the following:
“I want to overclock quite a bit, but I don’t want anything noisy, and I’m not going to pay a lot for that heatsink. What should I get?”
What they’re really saying is “I want to go to heaven, but I don’t want to die.”
Noise
You want quiet? Use water. You want air, you got to blow a lot of air on that CPU, and blowing a lot of air means noise. Spend less on a cheaper, less bulky heatsink, and you need a stronger fan. Even more noise. You don’t want water, and you don’t want noise, you don’t want a fast TBird.
Why the need for noise? That’s the second reason.
Heat
If we’re talking about 1.4 – 1.5, even 1.6Ghz, we are talking about dissipating 80-100 watts of heat. In comparison, a PIII at 1Ghz is about 35 watts.
Try grabbing a 35 watt light bulb, then grab one that’s 100 watts, and tell me it’s the same thing.
Yet that’s what a lot of you are effectively telling me. You’re looking at heatsinks that were great for cooling PIIIs, and you want to use the same thing to cool 1.5Ghz TBirds.
C/W Explained
When you look at Joe’s heatsink reviews, you see the term “C/W” used a lot.
C/W basically tells you how well a heatsink draws away heat. You take the wattage, multiply it by C/W, and the result is how much hotter the processor will get over the regular temperature.
Let’s give some real-life examples.
The very best heatsink/fans right now have a C/W of about .18. Right now, that’s the Swiftech MC-462 and the Milennium Glaciator, those two are in a class by themselves right now. Hopefully, more will be coming.
Once you get down to about the $20 range (the coolers I’m getting asked about), you’re usually looking at heatsink with a C/W of about 0.35-0.40. You can see C/Ws for a whole lot of processors over
Get down to $10-15 (which is about what AMD gives you with its retail cooler), and the C/W is more like 0.50.
What does that mean in real life?
Let’s take that PIII chewing up about 35 watts. Assume you have a temperature of 72 degrees (22C).
With the best heatsinks, you get: 35 X 0.18 = 5.6C increase over 22C regular temperature, which is 27.6C, or about 82F.
With the $20 heatsinks, you get: 35 X 0.38 = 12.6C increase over 22C regular temperature, which is 34.6C, or about 94F.
With the $10 heatsinks, you get: 35 X 0.50 = 17.5C increase over 22C regular temperature, which is 39.5C, or about 104F.
With a PIII, not even the $10 heatsink is too bad, and the best is overkill.
But we’re not talking PIIIs, we’re talking much faster, much hotter TBirds.
If we’re looking at 1400Mhz, about 1.85V, we’re looking at about 80 watts of heat that have to be taken care of.
Let’s do the math.
With the best heatsinks, you get: 80 X 0.18 = 14.4C increase over 22C regular temperature, which is 36.4C, or about 98F.
With the $20 heatsinks, you get: 80 X 0.38 = 30.4C increase over 22C regular temperature, which is 52.6C, or about 127F.
With the $10 heatsinks, you get: 80 X 0.50 = 40C increase over 22C regular temperature, which is 62C, or about 144F.
But for those of us who point our testosterone in this direction, we’re looking at get over 1500Mhz, and 1.95V or more. Now we’re looking at 100W or more.
Let’s just say 100W.
More math:
With the best heatsinks, you get: 100 X 0.18 = 18C increase over 22C regular temperature, which is 40C, or about 104F.
With the $20 heatsinks, you get: 100 X 0.38 = 38C increase over 22C regular temperature, which is 60C, or about 140F.
With the $10 heatsinks, you get: 100 X 0.50 = 50C increase over 22C regular temperature, which is 72C, or about 162F.
Do you see what’s happening. A PIII is no cooling challenge. Even a relatively lousy one doesn’t do too badly.
But a high-end TBird separates the men from the boys. When you double or almost triple the heat load, the differences between the good and bad ones really come out.
This is not going to change. Palomino will chew up less power, but still will spit out much more heat than that PIII. Run it at 1.8Ghz or so, and we’re back to the same situation.
Some Additional Points
These are maximum temperatures. These are the kinds of temperature you’d get running Prime95. If all you do is pop around the Web, you’re barely using the processor, and can be relaxed about these things. If you’re gaming, or anything else that’s pushing the processor to 100% often, these numbers are meant for you.
Temperature sensors can be wacky things, but I can tell you from my own personal experience over the last couple days with good but not the best heatsinks, these estimates are in the ballpark.
Athlons are hardier creatures than Intel chips, but you may start seeing sporadic freezes once the temperature gets into the 50s. Get into the sixties, and you’ll start seeing them regularly. Go over 70C regularly, and get ready to go into the keychain-making business.
Even if the processor doesn’t crash, higher temperatures means that natural processes like electromigration occur more rapidly. If you run your CPU at 60C all the time, the odds on it just not waking up one day are a good deal higher than if you ran it at 40C all the time (still not too likely even at 60C).
But I’m not going to overclock much
We’re reaching the point where it doesn’t even matter if you don’t overclock at all; you still need high-end cooling if you make your processor work hard.
At the moment, I’m running systems where the cooling is about in the middle category, and I’m telling you I’m antsy about it. Not while I’m typing this article, temperatures are no problem at all. But I can start running Prime95 or Sysmark2000, and I’ll be
looking at 53-55C with an Alpha PAL6035, at “just” 1333Mhz, and at “just 1.78V.” That’s a regular speed and a regular voltage. I would feel a ton better running at less than 40C instead.
I’m just not going to pay a lot for a heatsink, period.
This absolutely baffles me. You’ll spend $200 for a processor (or run it at a speed equivalent to one costing $200), and spend $1,000 or more on a computer, but you won’t spend $20 more on the one item that will protect that investment, and will to a large degree determine how far you can overclock.
If you buy a Ferrari, do you put all your money into the engine, and skimp on the radiator? That’s what you’re effectively doing by putting a cheap heatsink/fan on a high-end TBird.
These things pound out heat. That’s not my opinion; it’s an objective reality, and ignoring it doesn’t make it go away.
The only plausible reason I can see for this is “I’m not going to spend $40 for a $120 processor (or a $60 processor if it’s a Duron).”
Let me ask you this: if AMD started handing out Durons for $5 and TBirds for $10, would you then not spend more than a dollar or two for a heatsink? How far do you think that would get you?
Let’s say AMD doubled the price on CPUs? Would the exact same cooler be OK now that it’s protecting a more expensive processor? Even though it’s the same thing?
You buy whatever is necessary to keep the rest of your investment working well, and you add that to the overall cost. That’s how you should calculate what the CPU “costs” you.
You’re Just Pimping For Millenium!
I’m starting to hear that, let me say a few words about that.
Here’s what the owner of Millenium said about this in another forum (slightly edited for typos):
Joe Citarella has been kind enough to act as an advisor on design and marketing issues relating to adapting my technology to overclockers. I did not think the ease of clip attachment was a big deal; he told me to change it. He also advised changing the material from aluminum to copper and had significant input on final pricing. In exchange I act as a technical resource for OC.com, providing access to lab equipment some minor technical analysis on airflow issues. Joe is a real feisty guy; he can not be bought-by anybody.
Making it easier to put on, making it better, suggesting a lower price? If that’s pimping, we’re proud of it. We could use more of that kind of pimping rather than “give me a free one, and I’ll say it rules.”
Sure we like the product and are recommending it, because it’s a damn good product at a damn good price. It’s only competitor at the moment (and that may be a brief moment, though potential challengers seem to be coming in at about the same price), the Swiftech, costs twice as much. It also is quieter
You want to wait for other review sites to look at it? No problem, we have nothing to worry about.
If somebody else comes out with something better for the same price, or the same but cheaper, or a bit worse, but a lot cheaper, we’ll tell you about that, too.
The Point Of All This
If you want to play hard with high-end TBirds, you need high-end cooling, whether you overclock or not. An Alpha PAL6035 is hardly a crappy heatsink by past standards, but it creaks at 1333Mhz with a heavy load, and probably will buckle at 1500 or 1600Mhz.
If you’re going to keep it to 1.33Ghz or 1.4Ghz, you may get away with a $20-25 cooler with few problems, but to me at least, an extra $15-$20 is well worth the peace of mind it brings to not have to worry about heat-related crashes and possibly prematurely aging the chip.
If you’re going for the big 1.5Ghz or 1.6Ghz, you’re crazy if you don’t spend the extra $15 or so. That will probably mean the difference between success and failure. Sure, you might be able to get into Windows at 1.6Ghz and run Sandra at that speed with a cheapy, but can you do any real work at that speed?
I see so many comments in our database that basically say, “I have to get better cooling.” All those people ended up buying two heatsinks, the one they “saved” money on, and the one they ended up needing. They didn’t think they needed to spend extra, either.
There’s only one thing I want you to do. Before you buy anything, find out the C/W from a reliable source. Do the math like we did above. If you come up with an answer of 45C or less, that should be fine.
But don’t pretend the heat isn’t there, or buy something because it looks cool or has a cool name. These aren’t fashion statements. They’re real pieces of equipment that do real work, which is making things cool, not just looking it.
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