PC Cooling

The way that elecricity and electronics work means, that ultimately all the power that a computer consumes is converted into heat. That mans, that while your PC is sucking 700 Watts from the wall, it’s also functioning as a 700W space heater.

If those 700W worth of power are not adequately removed from the device (by blowing it into the surrounding room), then heat will accumulate, i.e. the device will grow hotter - until it overheats. It’s the job of the cooling system to prevent that.

Different Approaches

Different classes of devices have different ideas on how to keep themselves at working temperature. Office PC’s for example, typically encounter very bursty loads - that means they are not expected to run on full tilt continiously, but only see short spikes some seconds up to a few minutes at most, of high load. That means, even if they can use up to 700W, they don’t continuously do so, and thus can allow some heat to build up, which they can dissipate later, over a longer time period. Their cooling soltion doesn’t have to move those 700W - but can get away with significantly less.

Gaming computers on the other hand, are meant to run on near 100% power for extended periods of time - often for multiple hours straight. They are designed to be able to dissipate theoretically even more than those 700W maximum power, so that even when running on 100% load for hours, they stay well below maximum temperature. This is achieved through large fans blowing lots of air over large heat sinks. (Or large fans blowing lots of air over large radiators, in the case of water cooling.)

Laptops are designed for mobility. They are supposed to be carried around, and used off of batteries. Therefore their main goal is to use far less power in the first place - which then also requires far less cooling. Using far smaller fans and tiny heat sinks, their cooling solution still might still be considerably below what heat they can produce when running full tilt for extended time. They are not meant to do that.

Gaming laptops are designed for the impossible. Small and carryable but still powerfull and capable of running full tilt for extended periods of time while plugged into the wall. They can’t have large and heavy heat sinks, but they do the best they can by optimizing cooling efficiency and using loud fans. They can’t use the full-fat 700W hardware, but they do the best they can by optimizing power efficiency of less capable but still quite powerful hardware. Gaming laptops are a balancing act of many different compromises.

CPUs

The CPU or main processor of a PC is very much able to run at up to 100°C these days, and hit these high temperatures repeatedly, without any ill effect. If it does, it will automatically underclock itself - sacrificing performance - to avoid damage. While underclocked, less heat will be produced, and thus the temperatures can be kept at a stable 100°C and never get higher than that.

If underclocking were not enough to stabilize temperature (which typically should only happen if something is wrong) - then the CPU would automatically shut itself down. The PC would turn off, and typically you’d not be able to turn it back on again, until a few minutes later, when it’s a bit cooler again.

Office PCs are sometimes designed to rely on this underclocking feature. Apple did fully rely on automatic underclocking on almost all their Intel based Macs. Just because they didn’t want ugly air vents or loud fans, they left a lot of potential performance on the table. But unlike gaming PCs, these devices are not expected to run at full tilt for extended periods of time. Same goes for regular laptops.

Gaming PCs though (and gaming laptops as well), are expected to run at near 100% load for extended periods of time. Their cooling solution needs to be strong enough to handle the full max power that the device can draw - continuously. Some gaming laptops might struggle with that, and need some additional help, in the form of a dock with built-in cooling fans. But a gaming PC should be able to push enough air through itself, to be able to run at 100% CPU for hours without ever getting anywhere near those 100°C where it would throttle (underclock). And that should hold true, even in the case of overclocking or inefficient software.

The standard cooler that comes with a CPU in the box should be sufficient for office use - but for a gaming PC something beefier is required. Larger, heavier and stronger fans.

GPUs

When it comes to graphics, in the case of integrated graphics, those are simply a part of the CPU - and not it’s own thing. Full fat graphics cards though are definitely meant to run at full tilt and are gaming devices. They come with built in coolers that are fully capable of dissipating all the heat the card can produce. But they are reliant on access to fresh, cool air. It’s the job of the case and the case fans to deliver enough fresh air to both the GPU and the CPU.

If there’s not enogh cool air to be had, a GPU will throttle itself (i.e. reduce it’s performance to produce less heat) - first a little, then more severely. If that’s not enough to stabilize temperature, it will eventually shut down itself (screen goes black). This again is done to prevent actual damage to the card. Unlike office PC’s or integrated graphics though, dedicated graphics cards are not designed to rely on that throttling. They always come with enough cooling to stay below dangerous heat levels, even if run at full tilt for hours.

Overheating

As already mentioned, office PCs and laptops might actually rely on throttling to keep temperatures in check - as do smart phones.

A gaming PC though should never overheat, and never even come close to those dangerous temperatures. The cooling solution should be overspecced enough, to keep both CPU and GPU at more comfortable temperatures, even when running both at full load for extended periods of time.

There are things that can impact this cooling capability - fans might break, cooling paste might dry out, cooling fins might get caked in dust, air filters might clog up, case intakes or outlets might get blocked, coolers might not be mounted properly, vapor chambers might have leaked, etc. - but room temperature is a factor as well. A PC can cool itself better when inside a climate controlled room, vs. when in sweltering, tropical heat.

To make sure your PC runs optimally, you should definitely clean your air filters regularly, and also pop open the case every now and then, and empty a can of compressed air through the cooling fins, to avoid any dust build up in there. If your PC get’s older than 5 years, it might also be advisable to replace the thermal paste - by unscrewing the cooler, cleaning off the old paste, and applying some fresh new goop. Go watch a youtube video on how to do that, before you attempt it though. Also make sure that air vents aren’t blocked and that the flow of air is not obstructed.

You can also test if your PC is fine - there’s software specifically designed to do that: benchmarks. That’s software which does intentionally push your CPU and/or GPU to 100% for extended periods of time. It also measures performance and gives you a score - but for the purpose of testing thermals, you can ignore that. Just let it run and monitor heat - and make sure your PC can run at full tilt for hours without throttling or overheating.

Games and Software

It’s generally not the job of the software, to make sure your system does not overheat. Sure, games do offer graphics settings that allow you to lessen the load on the GPU - and those can be used to reduce thermal output - but that’s not why these setting exist. These settings exist to allow you to tune the visual result you can get, when running your GPU at full tilt - and to choose between tradeoffs like higher resolution or higher frame rate. On a gaming PC you should not have to use the settings to avoid overheating. A gaming PC should be fine running at 100% for hours, without getting near overheating temperatures.

There’s also some software that will tax the hardware a lot more than others - besides those benchmarks. Converting videos, compressing large files, compiling software, AI training, scientific calculations, cryptography, etc. - are all tasks that can push the CPU or GPU to 100% load for extended periods of time. These often do not even have any settings that could be used to keep load and temperature low.

Games do belong into the “very taxing software” category as well - which is why gaming PCs are designed to fully handle that heat. How much they tax CPU versus GPU varies from game to game. A well optimized game will provide a lot of visual oomph and tax both CPU and GPU in a balanced way. A badly optimized game (especially when there are memory leaks leading to memory shortage situations) might tax your hardware a lot more unevenly, and cause a lot of power draw and heat for unproportionally low visual returns. The actual power draw of the hardware at 100% load might actually vary slightly, depending on how balanced the load is.

Either way, the cooling system of a gaming PC should be able to handle running at the maximum possible power-draw, without running into throttling. A gaming laptop might take a hybrid approach to cooling, where it can just barely handle typical (more balanced) loads - but does have to rely on throttling in extreme scenarios. But a well-built, stationary gaming PC should have enough cooling headroom for any scenario - unless of course it’s power-draw has been increased to the edge by overclocking.

No software (well optimized or not) is designed to measure temperature and slow down to avoid overheating, because that’s generally not the job of the software to do. Software is supposed to do it’s job with whatever performance it is given/can request. Regardless of whether that causes throttling or not. It’s the job of the hardware to cool itself, to ramp up fans as needed, to avoid throttling if possible, to throttle if needed and to finally shut down if everything else fails. The software can’t know what temperatures are permissible for any given hardware, or what approach to cooling is being taken.

Conclusion

• Both GPUs and CPUs will throttle or even shutdown to avoid getting too hot and incurring any damage.
• Office PCs can rely on that for cooling - gaming PCs should not.
• A gaming PC should be fully capable of running at maximum power draw for hours at stable temperatures.
• If yours is not capable of doing that, clean the air filters, cooler fins, check that all fans are working, make sure airflow is not obstructed and maybe even replace the cooling paste.
• It’s not the job of any software to “hold back” to avoid high temperatures.
• Some software might cause more heat than others - the cooling solution should be able to deal with that regardless.