Single-thread performance it tied to clock frequency, which cannot go above 5Ghz, so the only thing we'll see is more cores. It is actually blessing in disguise, this is exactly why ancient Core Duos, made in 2007 are still perfectly usable for office applications and even lightweight development.
Where do you get this idea? Single-threaded performance has improved substantially in the past several generations of Intel processors. Single-threaded performance and clock speeds have not been correlated outside of same generation for a while now - like over a decade.
There's are 2.8GHz processors at the top of that benchmark with a 3100 score and one near the bottom with a 539 score, as well as everywhere in between.
Probably he based his opinion on speed of progress. In 2006 you could buy Core 2 Duo at 3.0GHz. Modern processor at 4.5GHz would be maybe just 3 times faster in normal, every day, single thread use which seems like a lot, but isn't too much if you think that CPUs 14 years before Core 2 Duo were clocked at 33MHz and IPC slightly below 1.
My dad uses a computer with C2Q CPU and it's still fast enough for everyday use.
Edit: to be clear, he's still wrong, we had quite untrivial IPC increase during all these years. I just wanted to point out that he's comment probably was based on empirical data.
5% increase per gen for most of the past decade vs. 50% increase per gen when clock speeds were increasing in lock step along with transistor count, but sure.
I've got a 13 year old laptop that runs today's OS's and development software a little slow but ultimately just fine, and if it weren't for a low limit on installed RAM it would be more than "ultimately" just fine.
That would've been absolutely laughable even 10 years ago, much less 20. You'd be lucky to be able to run a then-current OS on 2-3 year old hardware in the 90's through early 2000's.
Of course they are not linearly scalable across generation, but last significant performance improvement was in Sandy Bridge. Let's compare for example i5-2500 and i3-9100, more or less similar chips in terms of the number of cores and cpu freq. Their single thread performance (normalized per GHz) is within 25% from each other. In the last 10 years we've got 25% increase in IPC. If we compare with slightly more modern CPU's such i5-3570 it becomes even more laughable meager 10%. So, yeah we are reaching the limit of IPC, if not reached already.
> Single-thread performance it tied to clock frequency
Within an architecture, yes, but between architectures performance of different usage patterns may vary wildly.
> which cannot go above 5Ghz
this is objectively false. Intel is shipping (limited amounts of) chips that boost over 5GHz, and IBM is shipping its z15 z/architecture CPU which clocks at 5.2 GHz, and shipped its ancestor, the zEC12 CPU clocking in at 5.5Ghz (!), in 2012.
> Single-thread performance it tied to clock frequency
In a very loose sense.
It's clock speed * instructions per clock. But even that is misleading, as the number of instructions per clock is not a fixed quantity and hasn't been for decades now. It's also impacted by the instructions that came before and the ones predicted to come next.
> this is exactly why ancient Core Duos, made in 2007 are still perfectly usable for office applications and even lightweight development
They are suitable because these applications are not very demanding. A Core2Duo at the same clock speed of a modern processor will be much slower.
> cannot go above 5Ghz
Can, and have. But the cost-benefit of increasing clock speeds further is not favorable.
I know how CPU's work. Core 2 might be an extreme example, but IPCs between 10 years old Sandy Bridge and Coffee Lake differs only by 25(!) percent. So yeah, last 10 years, and especially after the Ivy Bridge, Cpu Freq almost linearly tied with the performance.
It is not bizarre at all. I find bizarre, OTOH when people fail to understand the context of the phrase. It is not normal to overspecify a statement, when it is clear what is the obvious meaning: a normal modern consumer-grade CPU in a typical usage environment cannot work at frequencies above 5Ghz. And that is true.
