Question Why is it so hard to find what the wattage rating on a CPU heatsink

In reality, don't use TDP as an accurate figure to determine whether a cooler can handle a CPU. TDP is wildly inaccurate for most Intel chips. AMD's TDP rating is typically closer, but not always 100%.
For example, the Core I9 9900k has a 95w tdp according to Intel. Without any overclocking, it pulls nearly 205 watts running prime 95. Over double its rated TDP!
 

lynx1021

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Feb 17, 2016
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It is just a pet peeve of mine, I was wanting to change my cooler and the ones I was looking at didn't show the wattage on the sales site or the Manufacture's site. I have tried googling but it seems like the info is not out there for what I was looking for. I remember when I could find a lot more answers on google 10 years ago , now when you search the just want to sell you something!
 

Gam3r01

Titan
Moderator
Generally speaking the listed (or lack thereof) TDP on coolers is not very well tied into performance.
Its generally better to look at performance benchmarks of the products to get an idea.

What cooler do you have now, and what are you looking to change about it?
 
Reactions: DMAN999
It's pretty easy to guess TDP and performance of air coolers, just look at number of pipes, their diameter and number, size of cooler body (which usually corresponds fan size). More of each and you get higher TDP.
Other things like number and shape of fins is largely a gimmick.
 
Aug 20, 2019
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Looking at different CPU coolers I can never find the wattage rating.
I ran into the same issue when researching Heatsinks. Some manufacturers list the TDP rating while others don't (Noctua, Scythe, etc.) I contacted Noctua to find out why that is the case and they gave me the following explanation (sorry in advance for the long read):

"The problem is that a cooler might be able to handle 250W TDP on CPU XX, however on CPU XY it was only capable of cooling 110W TDP CPUs. To use our coolers as a reference: The NH-D15 can handle about 130 Watts on the latest Ryzen 3000 CPUs while it can handle up to 400 Watts on the Ryzen Threadripper 2990WX CPU. Why the huge difference?
Many reasons for that - one being the different CPU DIEs; another would be the bigger heatspreader on the DIEs; and yet another reason is the used thermal interface material (TIM). And that is just to name a few of all the reasons for that. Now if we would start selling our NH-D15 with a "400W TDP" label, ... well I guess you can see that problem there. That would be yet another value that is not helping to compare coolers. It's just not that simple.

To sum it up: Noctua is not totally against submitting (peak) stats, but we hate the streamlined way those are published today. We try not to follow this trend - but are focusing on real world scenarios tests like independent reviews that are - in our eyes - the primary source for customers to see whether our products work well or not."

While it makes sense, I'm like you I guess: I want to see a number, even if it's an estimation, so I can have an idea of how much load the Heatsink can handle. Simply providing a TDP Compatibility Guide--as Noctua does--isn't enough since what they may consider to be suitable I may not. If my CPU is rated for 105W, and I want to only consider Heatsinks that can handle 200W or more, I have no way of knowing whether a particular Heatsink they suggest meets MY requirement, even though their TDP Guide says it's compatible. For all I know the Heatsink they suggest may only be able to handle 150W.

I did reply, giving them my PC build specs and asked if they'd give me a rough estimate of the TDP Value for the Heatsink I was considering purchasing from them, and guess what, even though it could handle the CPU TDP rating, it didn't meet my TDP requirement. So I looked elsewhere.
 
Reactions: TimH77 and DMAN999
Aug 20, 2019
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I like that they arent being misleading.
I don't view manufacturers that do list TDP values as trying to 'mislead' consumers since as it relates to performance data, the value listed is only based on the build on which the test was performed. It's virtually impossible to test a heatsink in every possible build configuration so whenever I research component specs, I realize the values are just estimates. Probably the only spec that is concrete is the dimension, shape and color of the component. :)
 
The situation would be helped if a certain company didn't rate TDP at the base clock that their CPU NEVER runs at under load.

The kind of engineers at a certain manufacture that say the I9 9900k is only 95w are like the philosophers that think the world is flat.
Except the ancient philosophers didn't know the truth, but the engineers know the i9 draws >200w. This still miffs me to this day.

To be fair AMD did the same thing with the 9590, which was much worse in every way, but at least AMD corrected their error and are more accurate now.
 
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Karadjgne

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Herald
That's only because many ppl are clueless as to exactly what constitutes TDP.

Thermal design power is the amount of power in watts used by a cpu (going with Intel version) averaged from a specific series of apps at base clocks without hyperthreading. Since the amount of watts used is within 5°C ± of most cpus, TDP as it applies to thermal watts was adopted as a general reference.

Which is why TDP is almost identical on an i7 or an i9 or an i5 in the same series/gen since it's all the same base clock speeds, all the same apps on all the same number of threads, one per core.

Apart from the i9 9900k, for Intel cpu's just figure a cpu cooler needs to be @ 1.5 to 2x TDP for stock gaming use, if introducing OC figure 2x to 3x. Err on the side of caution though, where an i5 would be ok with 1.5x TDP, an i7 with its hyperthreading would be better suited at 2x.

So a 9700k would be looking at the 180-220w range of coolers, which is the Cryorig H5, Dark Rock 4, Scythe Fuma2, Noctua NH-D14, most 240mm AIO's.

The 9900k requires no guessing or estimates. It's 200w output stock and upto 250w output at locked core turbo makes things simple. Cryorig R1, Noctua NH-D15/S, any 280/360mm AIO or full custom loop. Anything less and start looking at gaming temps over 70°C, Prime95 in throttle or capped thread usage.

With case size limitations put on cpu coolers, there's really only 1 rule. Bigger is better. You cannot Overcool a cpu, but it's far too easy to Undercool one.

Like psus, cpu coolers are components where budget should not apply, they are pc must have components, every other component is a luxury choice.

Guessing the wattage of a cooler is easy.

Stock intel @ 110w
92mm coolers @ 130w
Budget 120mm @ 140w
Mid sized towers @ 180w
Mid sized twin towers @ 200w
Full twin towers @ 250w

120mm aio @ 140w
140mm aio @ 200w
240mm aio @ 250w
280mm aio @ 300w
360mm aio @ 350w.

But obviously do apply a little common sense. A thin rad will be on the lewer end of the wattage range, whereas a thicker rad of the same size will be higher wattage.

If a cooler manufacturer feels spiffy about their product, they'll usually put the wattage, as it's usually a slight step up from the competition, such as the Cryorig H7 is 145w, just to stick it to CoolerMaster and its 140w hyper212 evo.
 
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DMAN999

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I personally always read reviews of any cooler that I am interested in, on the CPU (running at a reasonable OC), I have or am buying.
As long as it performs well on the CPU that I am going to use it on I don't worry about the Max Wattage rating.
My Ryzen 5 2600 is rated at 65W but I run it at a 4 GHz OC and hits anywhere from 80 to 100+ Watts under load.
As stated above, the size of the cooler and the number of pipes will be a good indicator of whether or not it will be sufficient to cool a given CPU.
For example my Arctic 33 eSports Edition dual fan cooler (supposedly rated for 210W max) is a mid sized 4 pipe cooler, that reviewed fairly well.
View: https://imgur.com/7NEbCrD

I would definitely not recommend it for a 105W or higher CPU.
It keeps my 65 W Ryzen 5 2600 at 29-30C at idle and maxes out at 60-61C while stress testing with Prime95.

You can search the Arctic site by Max TDP:
https://www.arctic.ac/us_en/products/cooling/cpu.html?cpu_cooling_capacity=111
 
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Aug 20, 2019
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That's only because many ppl are clueless as to exactly what constitutes TDP.
EXACTLY!! So for those people the TDP Compatibility Guide is fine. However, for the tech savvy people such as yourself and others--I'm not including myself since I'm still learning--I think an average figure should be included on their spec page. The same data/benchmarks they used to compile the TDP Compatibility Guide could've been used to include an average TDP value with the rest of the specs.
 
Well and the power a CPU consumes and the heat it outputs arent the same.

You could have a really good soldered tim on a CPU which would mean you could get buy with a cooler. If the same CPU had a crappy tim, the same cooler wouldnt work.
 

Karadjgne

Titan
Herald
Engineers are handicapped. They can't change the rules of TDP without revamping the whole thing, which at this point is about due. The methodology used was fine for anything upto the 8700k, quads have been around for years, but the move to Hexa-core doesn't work for apps that have limited usage of threads, none of those apps are open thread variable and able to use all 12 threads for a realistic TDP. So you get a series of apps built for quads, pushed on hexes. At base clocks.
 

TimH77

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Jul 21, 2017
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It is just a pet peeve of mine, I was wanting to change my cooler and the ones I was looking at didn't show the wattage on the sales site or the Manufacture's site. I have tried googling but it seems like the info is not out there for what I was looking for. I remember when I could find a lot more answers on google 10 years ago , now when you search the just want to sell you something!
I've been confused about TDP as well, while buying the parts to upgrade to an AM4. I see 65W TDP on a Ryzen 2700 and 105W on a 2700x... figuring I should see a similar number (or maximum TDP) on the mobo (which I can remember seeing when I first starting looking at upgrading a year ago.

For the first week or so, while looking for a motherboard, I was tracking my brain trying to find TDP numbers on different mobo's. After no success I ended up getting an MSI B450 Gaming Carbon Pro and a Ryzen 2700, figuring 65W was safe. But after posting and getting answers on here I'm sending it back and a 2700x is already on its way (before it's asked I didn't go 3700 because I'm not gaming but video editing and CAD).

So yes, it's confusing for newbies like me- some products with TDP and similar products without! Thankfully this forum filled with knowledgeable people is here or who knows what I would have ended up with! :p

(Side note) lynx1021- Your statement 'things are harder to find on Google' is not your imagination. If you haven't seen or heard about it, check out the document dump from a whistleblower.
 
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