AMD Ryzen 9 7950X3D vs Intel Core i9-13900K ?

[cyrilp]

Hi,
i'm about to buy a new computer, do you know wich one performs better with Metashape between AMD Ryzen 9 7950X3D vs Intel Core i9-13900K ?

[Bzuco]

Hi,

AMD 7xxx is better choice, because 13900k is mix of 8 performance cores and 16 efficient cores(without multithreading) and to match AMD performance it needs to be clocked almost to max boost frequencies, which produces a lot of heat.
Even better choice is AMD 7950X(non 3D), because that extra 64MB cache will highly probably not improve performance in metashape at all.
That cache is good only for certain specific games, which are heavily vectorizing data in CPU caches.

To get maximum potential performance you will need to undervolt the CPU in bios or in AMD software, because on default you can easily stuck on ~base multicore frequencies, high temperatures and high power consumption ...and that means lower performance in the end. This applies to all modern CPUs in the last ~10 years.

[DayGeckoArt]

Hi,

AMD 7xxx is better choice, because 13900k is mix of 8 performance cores and 16 efficient cores(without multithreading) and to match AMD performance it needs to be clocked almost to max boost frequencies, which produces a lot of heat.
Even better choice is AMD 7950X(non 3D), because that extra 64MB cache will highly probably not improve performance in metashape at all.
That cache is good only for certain specific games, which are heavily vectorizing data in CPU caches.

To get maximum potential performance you will need to undervolt the CPU in bios or in AMD software, because on default you can easily stuck on ~base multicore frequencies, high temperatures and high power consumption ...and that means lower performance in the end. This applies to all modern CPUs in the last ~10 years.

This seems accurate from what I know about the latest processors! But I recommend NOT undervolting unless you know what you're doing and know how to stress test. Undervolting is like overclocking, you can and probably will get calculation errors which can corrupt your data.

What you can do is use Eco Mode which I do with my 7900X. You can do it with the AMD software, or in the BIOS you can set power limits. I used the settings for the lower level 7900 non X processor to limit my wattage to 88W.

[Bzuco]

Undervolting is safe procedure, because it is about to find the lowest voltage which is not causing freezing and not the first one which causes issues. It is also adviced keep 0.02V reserve after finding the right voltage value.

Using ECO mode only helps to decrease power consumption and temperatures, but it also masivelly decrease performance because it is not based on undervolting principles.
https://youtu.be/RlMq1VEWNIM?t=84   that cinenebch is good representation how multicore performance dropped after eco mode enable.

What is even better is lock multicore frequencies to certain fixed value, e.g. 4.4/4.6/4.8GHz and do not use automatic boost single core frequencies...this makes undervolting much easier and more effective.

Finding the lowest voltage for CPU is much easier in ryzen master app then adjusting values in BIOS and restarting computer after each change. So it is 100% worth to do, otherwise we are significantly overpaying the performance. With undervolting we can also save money because much expensive water cooling solutions is not needed.

[DayGeckoArt]

Undervolting is safe procedure, because it is about to find the lowest voltage which is not causing freezing and not the first one which causes issues. It is also adviced keep 0.02V reserve after finding the right voltage value.

Using ECO mode only helps to decrease power consumption and temperatures, but it also masivelly decrease performance because it is not based on undervolting principles.
https://youtu.be/RlMq1VEWNIM?t=84   that cinenebch is good representation how multicore performance dropped after eco mode enable.

What is even better is lock multicore frequencies to certain fixed value, e.g. 4.4/4.6/4.8GHz and do not use automatic boost single core frequencies...this makes undervolting much easier and more effective.

Finding the lowest voltage for CPU is much easier in ryzen master app then adjusting values in BIOS and restarting computer after each change. So it is 100% worth to do, otherwise we are significantly overpaying the performance. With undervolting we can also save money because much expensive water cooling solutions is not needed.

Not freezing doesn't mean there aren't calculation errors. You would need to do real stability testing that looks for calculation errors, and you would have to do it outside the OS you're actually using

[Bzuco]

All of my CPUs were always undervolted and I never had problems with calculation errors even during  several hours of computing.

It is several times higher probabilty of errors in the system RAM modules affected with cosmic and electromagnetic radiation after several hours if modules don't have ECC correction. In that case money saved on CPU cooling can be used to buy RAM modules with ECC correction, like server computers have. Ryzen CPUs support this feature.

In case of exaggerated concerns and be 1000% sure, you can always leave a slightly higher voltage value than it is necessary for the proper operation of the processor. But it is still huge difference and big save in energy and heat compared to what we get from the factory with default settings. Manufacturers are keeping huge reserve because there is no time to test all chips to exact voltage needs.

Chips used in smartphones have much much less reserves in voltages compared to desktop CPUs, and are working several days without errors.

[DayGeckoArt]

All of my CPUs were always undervolted and I never had problems with calculation errors even during  several hours of computing.

It is several times higher probabilty of errors in the system RAM modules affected with cosmic and electromagnetic radiation after several hours if modules don't have ECC correction. In that case money saved on CPU cooling can be used to buy RAM modules with ECC correction, like server computers have. Ryzen CPUs support this feature.

In case of exaggerated concerns and be 1000% sure, you can always leave a slightly higher voltage value than it is necessary for the proper operation of the processor. But it is still huge difference and big save in energy and heat compared to what we get from the factory with default settings. Manufacturers are keeping huge reserve because there is no time to test all chips to exact voltage needs.

Chips used in smartphones have much much less reserves in voltages compared to desktop CPUs, and are working several days without errors.

You need to test! Period. You can't just say "Well I haven't had problems". You may not know if you've had problems, and you don't know if someone else will experience calculation errors. It's simply not true that cosmic ray RAM errors are more likely. The whole point of needing a certain voltage is that under that voltage you get calculation errors. You're basically telling someone a falsehood, that if the computer isn't freezing, there are no errors.

https://www.researchgate.net/figure/Number-of-faults-in-regard-to-overclocking-and-undervolting-for-matrix-with-size-of-10K_fig4_343556325

[Bzuco]

I have read the scientific article and checked their methods and graphs and this is my observation:

1. They tested GPU, not CPU.
There are almost no OS freezes, because graphics driver is restarted and recovered in case of GPU computation errors caused by low voltage.
In case of CPU computation errors, you may notice immediatelly blue screen/system restart, because CPU is managing whole system.

2. They choice GTX 980 which has 1126MHz base and 1216MHz boost frequency. That is how are set from Nvidia. Each Nvidia's partner is setting the boost frequencies even higher. In the article they started to check errors from core frequency 1404MHz up to 1806 which is considered as pretty high overclocking on default cooling solution.
You can clearly see(graphs figure 3 and 4), that if you do ~7.44% reduction of voltage(nice decrease of power consumption) for max. boost frequency 1404MHz(set by partner) there are no errors on this scientific level of measurement. It is sad, they did not publish exact volatage values.
The higher you go with frequency the lower posibilities are to undervolt, because for these frequencies the voltage/frequency in GPU's bios is not set. That scientific undervolting test doest not have much sense for overclocked frequencies.

What I am advising to cyrilp is easy and safe way where this scientific testing methods are not needed and the OS freezing test plus small voltage reserve after finding correct voltage for CPU is 100% enough for stable system with correct calculations. Otherwise as I said, I would be noticing constantly errors and bad strange results on everything I am doing on my PC with undervolted CPUs and GPUs almost 15 years.

My advised CPU undervolting knowledge are not falsehood.

The RAM errors caused by electromagnetic radiation are common, when users put their notebooks to sleep state over night(RAM modules still under voltage) instead of power off state. After two or more days strange things happens.