Why do GPUs get so much bigger than CPUs with every generation


Whats the technical reason with why the packaging of GPU and CPU are so different? Like why do go GPUs need such massive fans in comparison

In: 1

Effective CPU air coolers are very large.

GPU are getting so large because along with a fan or two or three, they also have a huge metal cooling system built into them.

If you look at old school GPU you’ll see they have a small single fan and open circuit board because they didn’t get hot enough to warrant a big cooling block.

If you look at modern performance oriented CPU air coolers you’ll see they are *massive*.

Power – GPUs are using 2-3x the power of the higher end CPU so they need 2-3x the cooling

Graphics workloads are the ultimate parallel loads so they can just throw more cores at the problem and get proportionately better performance so they do that which means that high end GPUs generate a lot of heat, like *a lot*.

A high end CPU might consume and dissipate 150W of power, this really pushes the little stock coolers to the limit so most people and computer makes that are putting a big powerful CPU in will swap for one of the larger tower coolers.

A GPU is a lot more power hungry. Top end cards are easily consuming 300W these days with big cards like the 3090 TI consuming 450W. That requires *at least* 2x the area/airflow of a CPU but a bigger heatsink and more fans gives overhead letting the card run cooler/quieter and live a bit longer, or letting users overclock the cards which pushes the power even higher

The big cards you plug in a PCIe slot aren’t just the GPU. They also contain the VRAM and IO as well as power converters and all these components need to be cooled too.

> Like why do go GPUs need such massive fans in comparison

[This is how a Noctua NH-D15 looks like in comparison to two recent GPUs](https://pbs.twimg.com/media/DuZ198YU8AATIY_?format=jpg&name=4096×4096). As you can see, the cooling solutions on graphics cards aren’t *that* big when you are comparing them to what goes on top of a higher end CPU.

It is simply a matter of GPU manufacturers having to sell the cards with a *good* cooling solution since aftermarket coolers are not easy to make or install, where a CPU manufacturer can just box their processors with an *eh, it won’t combust* grade cooler (looking at Intel) or just leave the cooler out and tell the customers to get an aftermarket beast like the D15.

GPUs are also a lot more power hungry, and the way they are installed means they need their cooler to push air the long way along the board and out on the rear panel, which is less efficient than a straight-through tower cooler.

Generalising here is a bit difficult, as you compare CPUs which range from 5-250 Watts of thermal design power with GPUs which range from 20-450 Watts of thermal design power.

My cpu (i3-9100F) has a much bigger cooler than my GPU (GTX1070) has, while the GPU die is 330mm^2 and the cpu die only 126mm^2 – both of them are around 60’C while gaming – the difference here is, my GPU is a lot more noisy! So I could have gotten a smaller cooler for the CPU, but then it would be the CPU fan that is noisy.

On to your technical reason, in a gaming computer, most of the processing is graphics related, so spending your power budget on the graphics card results in more useful work being done (higher frame rate). When more power is used, more cooling is required, so to keep everything nice and cool, more/larger fans are used. We also demand that these computers must not be noisy, so designers factor in extra heat sink size, so less airflow pressure is required to cool everything down, which makes things large again.