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TheSkiGeek t1_j6p44cp wrote

Reply to comment by Sneak-Scope in ELI5: Why do computers need GPUs (integrated or external)? What information is the CPU sending to the GPU that it can't just send to a display? by WeirdGamerAidan

That’s because GPUs don’t really cache anything, they’re running a program that streams data from one part of VRAM, transforms it, and writes it back to another part of VRAM.

If the OS wants to change what the CPU is doing it just jumps it to another block of code in RAM. Programs can spin up their own threads in real time. With a GPU there’s a whole process that has to be gone through to load or unload shaders, map and allocate VRAM, etc. — it’s much less flexible, and the latency of swapping from one kind of calculation to another is much higher.

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