[techpression]

The 7800X3D is amazing here, runs extremely cool and stable, you can push it far above its defaults and it still won’t get to 80C even with air cooling. Mine was running between 60-70 under load with PBO set to high. Unfortunately it seems its successor is not that great :/

[williamDafoe]

The 7000 series of CPUs is NOT known for running cool, unlike the AMD 5000 series (which are basically server CPUs repurposed for desktop usage). In the 7000 series, AMD decided to just increase the power of each CPU and that's where most of the performance gains are coming from - but power consumption is 40-50% higher than with similar 5000-series CPUs.

[scns]

When you use EcoMode with them you only lose ~5% performance, but are still ~30% ahead of the corresponding 5000-series CPU. You can reduce PPT/TDP even further while still ahead.

https://www.computerbase.de/artikel/prozessoren/amd-ryzen-79...

[techpression]

I specifically singled out the 7800X3D though, it runs incredibly cool and at a very low power draw for the performance you get.

[mldbk]

> You know, I'm something of a CPU engineer myself :D

Actually almost everything what you wrote is not true, and commenter above already sent you some links.

7800X3D is the GOAT, very power efficient and cool.

[Numerlor]

The only reason the 7800x3d is power efficient is because it simply can't use much power, and so it runs at a better spot of the efficiency curve. Most of the CPUs won't use more than ~88w without doing manual overclocking (not pbo). Compare that to e.g. a 7600x that's 2 cores fewer on the same architecture and will happily pull over 130w.

And even if could push it higher, they run very hot compared to other CPUs at the same power usage as a combination of AMD's very thick IHS, the compute chiplets being small/power dense and 7000 series X3D cache being on top of the compute chiplet unlike 9000 series that has it on the bottom.

The 9800x3d limited in the same way will be both mildly more power efficient from faster cores and run cooler because of the cache location. The only reason it's hotter is that it's allowed to use significantly more power, usually up to 150w stock, for which you'd have to remove the IHS on the 7800X3D if you didn't want to see magic smoke

[hu3]

Same for 9800X3D here, which is basically the same CPU. Watercooled. Silent. Stupidly fast.

[k4rli]

7900X same. System uptimes of 1month+ often and nearly always runs at 5.0Ghz. Never goes above 80c or so either.