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> showing 1 KB of text after 9 seconds is about a billion CPU instructions needed per character Correct me if I'm wrong, but on a 3ghz CPU (3bln cycles per sec

> showing 1 KB of text after 9 seconds is about a billion CPU instructions needed per character Correct me if I'm wrong, but on a 3ghz CPU (3bln cycles per second), there are 27 billion cycles per character for 1kb of text. Take into account that on any non-stone-aged CPU you've got probably 4-16 cores, and can do ~4-8 SIMD ops per cycle (at full clock rate), so at the limit we're actually talking .. something like _3.4 TOPS PER BYTE_ ..

jiggawatts 4y ago
A typical modern CPU can retire 2-3 instructions per clock, per core. Somewhat more due to hyper-threading, so maybe 5 per clock per core. So a 3 GHz, 8-core processor for 9 seconds is 5i x 3Ghz x 8c x 9s = 1 trillion instructions. Divide by 1KB to get roughly 1 billion instructions per character. SIMD is a little unfair, because virtually none of what an app like Teams does is amenable to vectorisation. If we allow SIMD, then we have to allow the GPU, and then we're talking about an entire different order of magnitude. A decent last-gen GPU has something like 30 teraflops, so about 265 billion instructions per displayed character!
- jesse__ 4y ago
  I didn't think about how many instructions a core could physically retire per clock, good point. > SIMD is a little unfair Yeah .. I agree, but I wanted to illustrate (to your point) just how much juice modern chips have.
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deathanatos 4y ago
Well, and then there's my work laptop which seems to enjoy clocking in at 800 MHz instead of the rated 3.4GHz because 60°C is too warm or so? But yeah, it is incredible when stuff used to load on single core 500 MHz CPUs. Or that I had a full graphical desktop on a 20 MHz CPU once. And it really wasn't that different? Launcher of apps at the bottom, even, despite being a completely different OS…
- justsomehnguy 4y ago
  Or what we had a web browsers running fine on 486DX4/100 (but without 59213857 emoticons, though).

jiggawatts 4y ago

A typical modern CPU can retire 2-3 instructions per clock, per core. Somewhat more due to hyper-threading, so maybe 5 per clock per core. So a 3 GHz, 8-core processor for 9 seconds is 5i x 3Ghz x 8c x 9s = 1 trillion instructions. Divide by 1KB to get roughly 1 billion instructions per character. SIMD is a little unfair, because virtually none of what an app like Teams does is amenable to vectorisation. If we allow SIMD, then we have to allow the GPU, and then we're talking about an entire different order of magnitude. A decent last-gen GPU has something like 30 teraflops, so about 265 billion instructions per displayed character!

jesse__ 4y ago
I didn't think about how many instructions a core could physically retire per clock, good point. > SIMD is a little unfair Yeah .. I agree, but I wanted to illustrate (to your point) just how much juice modern chips have.
- deleted 4y ago
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deathanatos 4y ago

Well, and then there's my work laptop which seems to enjoy clocking in at 800 MHz instead of the rated 3.4GHz because 60°C is too warm or so? But yeah, it is incredible when stuff used to load on single core 500 MHz CPUs. Or that I had a full graphical desktop on a 20 MHz CPU once. And it really wasn't that different? Launcher of apps at the bottom, even, despite being a completely different OS…

justsomehnguy 4y ago
Or what we had a web browsers running fine on 486DX4/100 (but without 59213857 emoticons, though).