3 ms·
Light travels at one foot per nanosecond. So a processor one foot wide you'd expect to run at 1 GHz max.
by sabbey 3y ago
Light travels at one foot per nanosecond. So a processor one foot wide you'd expect to run at 1 GHz max.
- _8j50 3y agoOnly if it is so badly designed that data needs to cross the entire dye's cross section.
- cma 3y agoLook at how much space cache uses on a die.
- _8j50 3y agoThe core would use cache near it? Memory access delay such as caches is not considered part of cpu frequency either afaik.
- tux3 3y agoCache takes X number of cycles to return a result You can make X lower by reducing the frequency (= having each cycle be longer) But apart for that, the main reason big chips would clock slower is power, not timing. If you have a lot of transistors all switching on a high voltage so that the frequency is high, you get molten metal and the magic smoke leaves. Big chips aren't one big stage where light travels from one side to the other. But they are giant weaves of heating elements that can't all run fast all of the time
- markhahn 3y agocache latency is definitely part of what limits core clock. you're not going to have a good time if your L1 latency is, say 10 clocks. not to mention the fact that register files are not much different than SRAM (therefore cache-like).
- _8j50 3y agoFair enough, to measure real world performance you're right anf that's all that should matter anyways.
- DeathArrow 3y agoIsn't Apple M3 larger in size than other Arm CPUs? Still, they don't run slower.
- smolder 3y agoThat's only if you needed a signal to cross the whole chip in one cycle. There's no such limitation preventing a 1 foot wide chip from being filled with 5ghz cores on an appropriate ring bus.