Discussion PES | Assessing Power and Performance Efficiency of x86 CPU architectures

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Det0x

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Sep 11, 2014
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Alrighty, have finally figured out my problems after a windows reinstall :)

Zen4 7950x @ 105 cTDP = 122w average power --> ~38.7k Cinebench r23 MT score
  • ST performance efficiently score = ~139
  • MT performance efficiently score = ~11599
1665607055843.png

Zen4 7950x @ 65 cTDP = 80w average power --> ~33.5k Cinebench r23 MT score
  • ST performance efficiently score = ~140
  • MT performance efficiently score = ~14202
1665607141679.png

Zen4 7950x @ 50w PPT limit = 50w average power --> ~24.8k Cinebench r23 MT score
  • ST performance efficiently score = ~143
  • MT performance efficiently score = ~14076
1665607244571.png

Zen4 7950x @ 35w PPT limit = 35w average power --> ~18.5k Cinebench r23 MT score
  • ST performance efficiently score = ~188
  • MT performance efficiently score = ~11525
1665607389595.png
 
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moinmoin

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Jun 1, 2017
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Zen4 7950x @ 65 cTDP = 80w average power --> ~33.5k Cinebench r23 MT score
  • ST performance efficiently score = ~140
  • MT performance efficiently score = ~14202
1665607141679.png
That MT efficiency at 65W TDP is insane. o_O

ST efficiency increasing at lower TDP shows that it's constantly boosting well beyond the efficiency infliction point. I guess only a fixed frequency could avoid that. (Or possibly a low temperature limit?)
 

Markfw

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That MT efficiency at 65W TDP is insane. o_O

ST efficiency increasing at lower TDP shows that it's constantly boosting well beyond the efficiency infliction point. I guess only a fixed frequency could avoid that. (Or possibly a low temperature limit?)
For an ASRock board/bios, all that I can find is if you use the max temp feature. No TDP setting or ECO mode that I can find (or anybody has told me about) Tight now I an running 90c, but might lower that later. I would LOVE to have that TDP feature ! It did lower the wattage, and I see no difference in times, but I am still at 35k on cb23.
 

Det0x

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Sep 11, 2014
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For an ASRock board/bios, all that I can find is if you use the max temp feature. No TDP setting or ECO mode that I can find (or anybody has told me about) Tight now I an running 90c, but might lower that later. I would LOVE to have that TDP feature ! It did lower the wattage, and I see no difference in times, but I am still at 35k on cb23.
You should have something like this in/around your PBO settings
1665610587435.png

If you have no eco mode you can set manually PBO PPT limit to 88w
1665610638216.png

If you don't have any PBO settings in your ASRock part of the bios, you should find this in the AMD part of the bios (advanced)
1665610707512.png

Hope this helps :)
 

Markfw

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You should have something like this in/around your PBO settings
View attachment 69008

If you have no eco mode you can set manually PBO PPT limit to 88w
View attachment 69009

If you don't have any PBO settings in your ASRock part of the bios, you should find this in the AMD part of the bios (advanced)
View attachment 69010

Hope this helps :)
Not on my screen... It was only the beta bios even had the throttle limit. I am on the latest beta bios.
20221012_135956[1].jpg
 

Abwx

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Apr 2, 2011
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Quite good efficency at 65W but when you do a compromise between pure perf and perf/watt then it s obvious that the 7950X really stretch its legs within a 88-105W range, at 65W the 7900X does almost as well despite the core count deficit at 87% of the 7950X@65W MT perfs.

Computerbase added a few numbers for the 7900X before ending its tests :


 

moinmoin

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Jun 1, 2017
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at 65W the 7900X does almost as well despite the core count deficit.
Ignoring the uncore overhead (so these will likely be worse in reality) 7900X should achieve a similar MT efficiency at around 49W, likewise 7700X at around 33W and 7600X at around 24W, lol...
 

Markfw

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I found a setting that I like ! I tried PBO and 170 watt, and somehow when I booted it was very slow and said 0 is the PPT. So on a different screen I found something that said offset, (negative) and I set that to 25. When I booted and I run cb23, it says 142 watt and 13 watt SOC, so less than 170 ! And the temp at 90. cb23 still running, I will update when it finishes !

Edit: First run 35,436 . So it did not affect performance at all and uses the same power as a 5950x now !

I am happy. This is what I wanted when Zen 4 came out.
 
Last edited:

Hitman928

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Apr 15, 2012
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I found a setting that I like ! I tried PBO and 170 watt, and somehow when I booted it was very slow and said 0 is the PPT. So on a different screen I found something that said offset, (negative) and I set that to 25. When I booted and I run cb23, it says 142 watt and 13 watt SOC, so less than 170 ! And the temp at 90. cb23 still running, I will update when it finishes !

Edit: First run 35k and change. So it did not affect performance at all and uses the same as a 5950x now !
A -25 offset is pretty large across all cores. It might not be really stable with that large an offset but who knows, maybe you got a top chip.
 

Markfw

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A -25 offset is pretty large across all cores. It might not be really stable with that large an offset but who knows, maybe you got a top chip.
Well, after prliminary tests, it looks fine, so I rebooted linux, and now am running 30 WCG tasks and the 3090TI is running F@H, so its maxed. We will see how it does.
 

.vodka

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Dec 5, 2014
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3900X + PBO fmax enhancer (ASUS' official EDC bug for Zen2), stock PPT TDC EDC (142w 95A 140A), 1900MHz fclk / 1900MHz uclk / 3800MHz mclk so the I/O die eats some more into the total power budget than usual.

Really nice to see efficiency going up with newer generations. Zen4 in particular is insane. Good stuff!

----------------

edit: I was curious what would happen if I gave it a higher power budget. So, 180W PPT (~20w for the I/O die plus some headroom for the cores), 110A TDC, 140A EDC (can't go over 140A on AGESA v2 >1.2.0.3c or else you get a 1.42v voltage cap)



It's become more efficient at least on this workload, lol
 
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Markfw

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I just realized. My new 7950 at 142 watts, is it on your chart ? I normally let it run linux, but I could install office and try it at 142 watts, but didn't detox do this at all sorts of wattage settings with his 7950x ?
 

BorisTheBlade82

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May 1, 2020
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So after having been some days off, quite some catching up to do...

@Det0x
These are some quite impressive results. Your 65w cTDP numbers are a bit better than the ones I got from Andreas Schilling - so you might have a Golden Sample ;) Aside from changing the cTDP did you tune something else as well? What kind of RAM do you have (although CB23 should not be very sensitive in this regard)?

I just realized. My new 7950 at 142 watts, is it on your chart ? I normally let it run linux, but I could install office and try it at 142 watts, but didn't detox do this at all sorts of wattage settings with his 7950x ?
No, but I will add the 105w and 65w cTDP numbers of @Det0x shortly. In the past I tried to only include stock results in order not to clutter the rankings. But I have a feeling that with this generation from both vendors the interest regarding performance and efficiency under limited TDPs has been growing lately.
So I will also re-add the 12900K@125w TDP for the sake of comparison.

/edit:
@Det0x
Would you mind doing another run with stock settings? Your 105w TDP run was already faster than the only stock-run I have of the 7950X until now.
 
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Markfw

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So after having been some days off, quite some catching up to do...

@Det0x
These are some quite impressive results. Your 65w cTDP numbers are a bit better than the ones I got from Andreas Schilling - so you might have a Golden Sample ;) Aside from changing the cTDP did you tune something else as well? What kind of RAM do you have (although CB23 should not be very sensitive in this regard)?


No, but I will add the 105w and 65w cTDP numbers of @Det0x shortly. In the past I tried to only include stock results in order not to clutter the rankings. But I have a feeling that with this generation from both vendors the interest regarding performance and efficiency under limited TDPs has been growing lately.
So I will also re-add the 12900K@125w TDP for the sake of comparison.

/edit:
@Det0x
Would you mind doing another run with stock settings? Your 105w TDP run was already faster than the only stock-run I have of the 7950X until now.
BTW, my results were from setting PBO(some sub-option) to -25 and max temp to 90. Its just so happens that Ryzen master now says 142 watt cpu and 13 watt SOC. You might want to put that in your notes.
 

BorisTheBlade82

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May 1, 2020
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@Markfw
Yep, understood. That is why I refrain from putting them in the rankings. When we start chasing down that rabbit hole of max. temp settings, Vcore offsets and stuff, we will never see the light of day again - I hope you understand ;)

So I just updated the rankings and included the results from @Det0x with 65w and 105w cTDP as well as @.vodka 's 3900X (to my own surprise we did not have a sample of that before).
 

Markfw

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@Markfw
Yep, understood. That is why I refrain from putting them in the rankings. When we start chasing down that rabbit hole of max. temp settings, Vcore offsets and stuff, we will never see the light of day again - I hope you understand ;)

So I just updated the rankings and included the results from @Det0x with 65w and 105w cTDP as well as @.vodka 's 3900X (to my own surprise we did not have a sample of that before).
BUT, my motherboard has NO ECO setting. Obviously the bios are very different. But any sane person would not leave bios at stock for Alderlake, Zen4 or Raptorlake IMO. So we really need to figure out the best way to determine efficiency, and wattage at full load would seem to be it.
 

moinmoin

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@BorisTheBlade82
Would it be possible to insert an average lines on the chart for CPUs with multiple results? That way many possible parameters could be covered over time without adding more points for each single one.
 

Det0x

Senior member
Sep 11, 2014
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So after having been some days off, quite some catching up to do...

@Det0x
These are some quite impressive results. Your 65w cTDP numbers are a bit better than the ones I got from Andreas Schilling - so you might have a Golden Sample ;) Aside from changing the cTDP did you tune something else as well? What kind of RAM do you have (although CB23 should not be very sensitive in this regard)?
Runs were done with PBO CO enabled, handtuned for my cpu with golden CCD0 (SP121) and below average CCD1 (SP112).
Memory were running at 4800MT/s with all stock voltages and timings.

@Det0x
Would you mind doing another run with stock settings? Your 105w TDP run was already faster than the only stock-run I have of the 7950X until now.
Yes i can do a new run at "optimized bios settings" (all stock) in the next few days
 
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