[bruce511]

One way to answer this question is to look at the software produced when clock speeds were 20x slower.

The limitations, and features we had then are a minimum starting point.

So I'm thinking around the era of a 486 100mhz machine. We'd have at least that (think mylti-player Doom and Quake era as a starting point.)

We had Windows, preemptive multi threading, networks, internet, large hard drives, pretty much the base bones of today.

Of course cpu-intensive things would be constrained. Voice recognition. CGI. But we'd have a lot more cores, and likely more multi-thread approaches to programming in general.

[saltcured]

Right, clock speed seems like a distraction to me.

A 20x reduction really isn't that significant in a historical context. Gray beards here have seen CPU performance increase by 200x or more over their computing careers since the late 80s or early 90s. And that is ignoring multicore/SMP gains.

I found this nice figure trying to summarize CPU performance trends over many decades: https://www.researchgate.net/figure/CPU-performance-Historic...

Prognostication depends on other unstated assumptions about the market or fundamental technological limitations. Generally, I'd say that if the single CPU core trend was more flattened, we would have seen more emphasis on parallel methods including SIMD, multicore, and the kinds of GPGPU architecture we're already familiar with.

The kind of programming model that is at the heart of CUDA, OpenCL, etc is exactly what the high-performance numerical computing researchers were using back in the late 80s to early 90s when computers were much slower. They were simply applying it to exotic multi-socket SMP machines and networks of computers, rather than arrays of processors on a single massive chip.

[Retric]

Even modern cellphone chips a far more than 20x the speed of a 100Mhz 486 outside of extremely pathological workloads. At minimum we’re still talking 64 Bit chips.

However, IMO simply thinking in terms of actual chips that existed isn’t that interesting. What would computing look like if the PIII was a 12 CPU at 500 MHz. That’s a little closer to 5% of modern chips and something nobody worked with.

Alternatively what the 486 era would have looked like with gigabytes of RAM and an SSD?

[mywittyname]

I can't buy into the idea of 486s but also SSDs. Why doesn't the speed limitation of CPUs extend to controllers, busses, SoC, transistor sizes, etc? If the 2GHZ CPU is now 10Mhz, then presumably the memory bus is no longer 100Mhz, but 5Mhz.

[Retric]

I think the basic assumption is some kind of change to the laws of physics and thus transistor frequency scaling otherwise it’s effectively just asking what it was like in the past. So dropping 6GHz 64 bit chips to 300 MHz doesn’t imply everything else is the same and where just using 32bit PII era hardware.

Similarly rather than NVMe 2TB SSD’s at 6000 MB/s we could have 2TB SSD’s at 300 MB/s. Which then opens the door for even more extreme differences.

If the “PIII was a 12 ^core^ CPU at 500 MHz” that’s quote odd by historic standards.