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Joined 1 year ago
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Cake day: June 8th, 2023

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  • Computer engineer here. I think physically swappable CPUs could be physically doable. You would have something like an SD card slot and just be able to click it in and out.

    The main problem is the speed of electricity. Electricity moves about as fast as light does, but there’s a problem. Meet the light nanosecond. The distance light travels in a nanosecond:

    It’s 6mm less than a foot. If you have a processor running at 4GHz, the pulse of the clock is going to be low for an 8th of a foot and high for an 8th of a foot. You run into issues where the clock signal is low on one side of the chip and high on the other side of the chip if the chip is too big. And that’s saying nothing of signals that need to get from one side of the chip and back again before the clock cycle is up.

    When you increase the distance between the CPU and the things it is communicating with, you run into problems where maybe the whole wire isn’t at the same voltage. This can be solved by running more wires in parallel, but then you get crosstalk problems.

    Anyway, I’m rambling. Main problem with multiple CPUs not on the same chip: by far the fastest thing in a computer is the GPU and the CPU. Everything else is super slow and the CPU/GPU has to wait for it. having multiple CPUs try to talk to the same RAM/Harddrive would result in a lot of waiting for their turn.

    It’s cheaper and a better design to put 24 cores in one CPU rather than have 12 cores in two CPUs.

    Most things are still programmed like they are single thread and most things we want computers to do are sequential and not very multi-threadable.