Why are GPUs so big, while CPUs are so small?
In: Engineering
The actual chip on a GPU isn’t too much bigger than a CPU. (I’ll come on to that). Instead, a graphics card is an entire computer in one. It has power delivery systems, voltage regulators, video memory, an I/O aswell as a microprocessor. So it is doing what the CPU, RAM and motherboard is doing in one. It is thus quite big.
The actual chip is a bit larger than the CPU because it is often much more powerful than a CPU at its specific tasks, so requires more silicon.
Because GPUs essentially integrate the processor, motherboard, ram, heat sink, and fan into one unit.
GPU is basically it’s own entire extra computer. The compute chip, It’s own memory, it’s own IO, onboard power management, the cooler, an abbreviated case holding the entire assembly together, the only thing it doesn’t have is storage.
But really, it’s not like the electronics couldn’t be packed smaller, they absolutely can. But the true limiting factor is cooling. You have so much power use, therefore you need that large of a heatsink, that much of a fan etc. That is what truly sets the size.
The gpu isnt realy that big but it has to have alot of other stuff around it mostly cooling that makes it very big.
And GPUs need a lot of cooling because they produce a lot of heat usually much more than the CPU.
Basically, the GPU comes attached with its own motherboard that holds all of the other components needed for the GPU to do its job. GPUs come with their own VRAM, while the RAM for the CPU comes in their own sticks that need to be connected to the motherboard. GPUs come with their own cooling solution (fan and a heat sink) where the CPU needs you to stick one on. GPUs come with all the chips and circuits needed to interface through the PCIE slot; that slot and the components needed on the CPU side are all integrated into the motherboard. Really, you’re not comparing the GPU *chip* to the CPU *chip*, you’re comparing the entire GPU board to the CPU chip.
You can see [from this partly disassembled GPU](https://madpcb.com/wp-content/uploads/2020/12/Graphics-Card-PCB-Assembly.jpg) that the chip itself is more or less the same size as a CPU, even a little smaller. You can also see the “Memory” label pointing to the VRAM.
Everybody answers the obvious, but not the WHY? Why the motherboard doesn’t have all the rest, and there would just be a socket for GPU, like there is for CPU
GPU has its own build in fans. A more fair comparison would be to compare the size of the GPU to the combination of processor+fan/coolor+motherboard+ram
as the others have answered gpu is a whole system in itself. but then question arises, why do we need cpu. there is an interesting GIF which shows that a train with a person in front who is laying the track while sitting in front of the train. that person is cpu and train is gpu. cpu lays the track so that gpu can run.
Wait a minute, are we talking about graphics cards or GPUs? GPUs are the big chips on the graphics card that do the actual work.
Why are GPUs so big and CPUs so small? Because GPUs contain a lot more transistors than CPUs. Why do they contain more transistors? Because it is much easier to throw more “workers” at the things GPUs do, so it makes sense for GPUs to have more “workers”. Graphics (and some other computing problems) is usually a bunch of relatively simple computations, but a shit ton of them (e.g. calculating the color of a pixel on screen is not complex, it’s just that there are so many pixels). CPUs on the other hand usually do a few computations that are relatively complex (with many steps that also depend on the result of previous steps and sometimes steps are taken depending on the results of previous steps and sometimes they are not taken).
The GPU chip isn’t that much bigger from a CPU. It’s the card that’s big. The GPU has to have additional features like a PCIe port, fan, its own power circuitry, etc.
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