All Gaming Laptops Overheat… but WHY?
At this point, I’ve reviewed a fair few gaming laptops, tested a whole load of different CPU and GPU combinations, and in those reviews especially for the CPUs I normally talk about the power consumption. You’ll see graphs like this showing the peak power usage under full load, normally while rendering the Gooseberry scene in Blender, or one like this showing the stable power draw, where the chip sits when it drops down off of boost. But there’s one graph I almost never show and that’s this, the temperatures.
But why? I hear you ask. Well, take a look. Here’s the last 23 laptops (and modes) I’ve tested. Notice the problem? The lowest result here is what? 91°c? It doesn’t matter if it’s a thicc-boi monster, a literal Xeon workstation, or a thin and light ultrabook, they are all over 90°c and most sit at 95°c or higher. It doesn’t even matter if it’s Ryzen or Intel, they ALL run real hot, but again, why? Let me explain.
I think it’s best to start by providing some context. I’ll show you that graph again, but this time add in a couple desktop CPUs. See the difference? Even a 12 core, 142W chip can sit in the 60-70°c range under full load. Compared to the 60W 8 core laptop chips, that’s an absolute monster and yet runs almost 1/3rd cooler. In fact, when it comes to desktop parts, anything above 80°c is generally pretty toasty, and if any of your parts are even close to 90°c that’s generally seen as a problem you want to resolve. So, if 90°c is awful on desktop, why do we just accept upwards of 95°c in laptops?
In short, performance. Desktops have the advantage of drawing as much power as they like which means you can get a whole lot of performance out of them, but laptops don’t have that luxury. We constantly demand more performance from them, we want that gap to desktop hardware closed as much as possible, so having their chips boost as hard as they can until they overheat then basically have them ride that limit until the workload is done is the way to squeeze out some rather impressive performance.
For some context, most of the 8 core mobile chips offer about the same performance as a desktop 6 core like the 5600X or 11600K, which considering the latter runs at almost 150W to do so compared to around about the 60W mark for Ryzen mobile or more like 90W for Intel mobile, that’s rather impressive from the laptops.
But, why can’t the laptops just run the same power levels as desktop chips and get all the performance possible? Well, again in short, physics. There are two main problems with laptops running high power CPUs: heat and power delivery. Let’s start with the latter. Even if you rule out running full power when on battery, to draw 140W from the CPU alone you’d need to use a power brick capable of delivering a fair bit more power than standard. Even a 240W power brick isn’t really feasible, which is why many of the insane machines come with two instead. You then have to deliver that power to the CPU through VRMs, which to manage that amount of power will need to be rather beefy – both of those things add cost pretty considerably.
The bigger issue by far though is heat. Remember that desktop CPU that draws 142W? Well what you cool that with is something like this, a 240mm AIO liquid cooler. The radiator alone is easily twice as thick as this entire laptop, and that’s just the cooler. The motherboard has it’s own heatsinks for those beefy VRMs, you have fans to blow air over them and plenty of air flow all round. Compare that to laptop internals and you’ll quickly find the issue. Look how little heatsink surface area there actually is, and what is there is shared with the CPU, GPU, VRAM and VRMs. You’ve got heat pipes that are connected across both the CPU and GPU, and the GPU almost always gets more heatsink material as it’s almost always significantly more power hungry and arguably more important for gaming performance anyway.
To dissipate well over 100W from the GPU and up to 100W from the CPU, you need a whole lot of heat sink surface area for that heat to be expelled from and a lot of air flow too, hence the jet turbine fans. Laptops generally trade noise for cooling efficiency, spinning their fans at 3/4/5/6,000 RPM, versus many PC fans that’ll barely tick over at 500, 1,000 RPM and often max out at around 2,000 RPM. They also often have a very different blade design much more similar to a GPU blower fan as they are front intake, side exhaust rather than a desktop fan which is front in, back out.
Now of course you can solve the heat problem, actually pretty easily, just add more heatsink material and larger fans but that comes with plenty of tradeoffs. It’ll be thicker, which in a world where all of our tech products are trying to be thinner and lighter doesn’t seem to be an option. It’ll be heavier too, obviously, but it will also be more expensive. There are gaming laptops that do actually use desktop CPUs like the Alienware AREA 51M, but that’s real thick and real expensive and still doesn’t run quite as fast as a desktop with the same hardware again thanks to thermals.
So, will a gaming laptop ever be as fast as a comparably spec’d desktop? Generally speaking, no. Mainstream machines like Asus’ STRIX G15, Acer’s Triton 500SE or Helios 300, or even XMG’s Core 15 likely won’t be rocking any CPUs or GPUs that can outperform or even match similarly spec’d or priced desktop parts any time soon. And, so long as we want the most performance possible out of our laptops, they’ll continue running as hot as they physically can while in use.
It’s also worth noting that generally speaking, the lifespan of silicon dies is based on their usage and especially their temperature. Laptop chips that run this hot are more likely to fail considerably sooner than a desktop chip that is well cooled – it’s not likely to be a concern in its “usable” lifespan but it is worth mentioning.
