Comment by mindslight

3 days ago

From what I've seen the whole PC review industry operates on emotional narratives rather than scientific measurements. When is the last time you saw a cooler spec'd by its thermal conductance (Watts per degree C) as opposed to a whole rigamarole of we used so and so RGB motherboard with so and so PC case and this version of Windows with so and so benchmarking software. And every cooler in the limited set we compared it to was worse, but of course we left a whole bunch out. Like sure integration testing can be useful, but it doesn't beat characterizing units in isolation with hard numbers. And they never reduce the number of variables enough to do that.

Part of the problem is that any given cooler doesn’t have a single W/K value. It depends on the temperature gradient across the heatsink which depends on airflow over the heatsink (and both the heat and heat density of the CPU being cooled), and the airflow depends on the case (and fans). And airflow temperature matters too (are you cooling the CPU’s heatsink with air that’s already been warmed by a GPU?)

Note as well that I said heat density - different benchmarks (or applications) will load the CPU differently, and the same amount of power consumption will result in very different heat outputs (heavy single core use will result in part of the die and heat spreader getting really hot, whereas heavy multi core use will result in the whole die and heatspreader getting kinda hot). If the heatsink has a very high surface area and high airflow it might have the ability to dissipate quite a lot of heat, but if the contact surface sucks (or is aluminum) it might not actually be able to transfer heat away very effectively without a massive temperature delta - resulting in high CPU temps for single core use even with a high cooling capacity for multi core use, for example.

Your average person can’t understand all of these variables, and the average reviewer can’t control for all of them. So, “this CPU with these benchmarks in this case with this fan configuration” is the best you can really expect. Because otherwise, what reporting are you actually going to do? “This cooler with 3.2CFM of 26C airflow on a CPU dissipating 80W on one core and 10W on the other 7 cores results in a peak core temperature of 87°C and a package temperature of 81°C” is not useful reporting. Especially because, when the average person doesn’t understand it, they’re gonna buy a case fan that says 3.2CFM on the box and then wonder why their CPU’s throttling.

  • Sure, but the goal of science is to distill these variables down into a model of what matters. Define a reference contact patch that's supplying the heat, and you've suspended all of the concerns about single core vs multi core. Then for more in depth articles, there could be a few to represent single core (smaller area), multi core (consumer processor), and multi core (larger server packages). Same with the airflow over the secondary parts of a cooler.

    Another in depth article could then even analyze CPUs and how they themselves differ from that reference contact patch, and their own thermal resistance from each core to their surface.

    And yeah, I know this is more work. The point is that doing the work allows the results to be used and compared across articles, even when some things are subtly different (eg contact patch). The problem is we're missing a strong incentive for these things to be objectively comparable, rather than having to read article after article and getting tripped up in the details.

    • The incentives aren't there (in my opinion) because the average person doesn't actually want to see that level of info. They're reading (or more likely, skimming) these sorts of reviews to have someone tell them what they should buy. The reviewer could go into a crazy amount of detail to figure out all of the thermal characteristics of the thing they're reviewing, but in the end it won't make a lick of difference compared to doing "just enough" and recommending something "good enough." Especially when, in most cases, coolers on the market these days are either "good enough or better" or "junk" and it's not hard to tell them apart.

      There are exceptions to the above, like GamersNexus, who do take a slightly more scientific approach to things, but at the end of the day, most people don't care.

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