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Has anyone done a perf / watt scatterplot of the current AMD and Apple offerings? I'd guess this wins in absolute performance (due to the TDP), but I've heard

by hedora 3y ago

Has anyone done a perf / watt scatterplot of the current AMD and Apple offerings? I'd guess this wins in absolute performance (due to the TDP), but I've heard AMD is pretty competitive on energy efficiency too these days. I'm typing this on an M2, which is simultaneously cooler and faster than my old Intel laptop. Wondering if it's time to upgrade my decade-old Intel Linux desktop to an AMD yet.

maccard 3y ago
I have an older threadripper - a 3970x. It's the most power hungry device in my house after my electric oven. In raw numbers it's hard to beat. But it is _not_ efficient
- hamandcheese 3y ago
  That is now a two generation old CPU at this point - I don't think we started seeing AMD get competitive on power efficiency until Zen 3.
- jrockway 3y ago
  I have the same chip and it's amazing to see it idle at 75W after growing up on Intel chips that use like 5W at idle. Of note is that Zen 2 (the 3970x's microarchitecture) is 7nm. The new Threadrippers are on a 5nm process. I would expect slightly lower power consumption, but note that the 7000 series of Threadrippers quote a TDP of 350W while the 3000 series quote 280W. So I'm guessing they're using the efficiency for more speed instead of more power savings. To me, it's fine. I'd always prefer paying more for electricity than to wait longer for something to complete. (But I do respect the desktop chips that can blink my cursor with an efficiency core that uses a few tens of milliwatts.)
- dathinab 3y ago
  Zen 4 is known to be noticeable more efficient then Zen 3 and even much much more so then Zen 2 so I don't think this comparison is helpful.
- pleoxy 3y ago
  All of the AMD chiplet based designs do poorly at idle power. These monsters will do better than the 39xx because of the 6mm IO die. But it's still going to have high idle power compared to a monolithic Intel design. The monolithic AMD dies (laptop/mobile) are competitive in the idle power space.
protastus 3y ago
I have a 16-core Ryzen 7950X that I run in "eco mode 105W". This delivers performance close to an Intel 13900K but at less than half the power. It's also much easier to cool and get a quiet PC without water cooling and enthusiast shenanigans (de-lidding, etc.) I don't know if the Zen 4 Threadrippers can be similarly run with a power limit. If they can, I'd expect much better efficiency than whatever Intel offers. This has eco mode benchmarks: https://youtu.be/W6aKQ-eBFk0?si=o8l1qGUhSQKxmY_c https://youtu.be/W6aKQ-eBFk0?si=o8l1qGUhSQKxmY_c
kcb 3y ago
Surprisingly haven't found great comparisons. A 7840U vs M2/Pro test would be pretty interesting. https://www.notebookcheck.net/R7-7840U-vs-M2_15023_14521.247596.0.html https://www.notebookcheck.net/R7-7840U-vs-M2_15023_14521.247... The last benchmark is interesting but unfair given that's an ancient application with Rosetta.
JohnTHaller 3y ago
> I'd guess this wins in absolute performance No need to guess: An M2 Ultra will get around 27,000 in Cinebench R23 while this Threadripper will get around 100,000. The M2 Ultra has a TDP around 90 watts (~ish according to a couple reviews) and this Threadripper has a TDP of 350 watts.
- smolder 3y ago
  There's some more nuance to efficiency than just max power at max load, of course. The Apple chips will likely have good efficiency compared to the lower core count (say, 32) TR because the watts per core gets high on those smaller TR chips. Yet if you compared their performance at a fixed 90w, I suspect the threadripper would come out ahead, since chips are much more efficient when at fractional loads that don't lead to boosted core clocks. Then again, at idle, the TR is probably guzzling power relative to the M2 Ultra. I'm only speculating to illustrate; a thorough comparison of their perf/watt characteristics would involve sampling many types of workloads of varying thread counts and levels of per-core saturation.
- arp242 3y ago
  If you underclock the Threadripper to get a score of ~27k, then how much power will it use? I wouldn't be surprised if it was roughly equal to 90W, or even lower. The stock configurations for a lot of desktop chips is to get the maximum performance at the expense of power, especially for things like these Threadripper series which are explicitly aimed at maximum performance. Often even drastically reducing power usage only gives modest performance penalties.
  - mafuy 3y ago
    Yes, cutting power targets of a (Desktop) Ryzen to 65W or 90W reduces performance to around 50% or 80% in some benchmarks, iirc. Likely a good tradeoff in many scenarios. I also run an RTX 3900 GPU at 60% power for 80-90% performance. It's a noticeable decrease in requisite cooling.
  - mrbigbob 3y ago
    Yeah I am definitely not a fan of Intel/AMD/and even Nvidia who will completely push power to stupid levels just to get less than an extra 10% performance Gamers Nexus did a video earlier this year comparing the 7950x at different eco modes and they found that putting the 7950x at a 105 watt eco made drop the performance around 5% but shaved almost 100 watts off of power. heres the link to the video https://www.youtube.com/watch?v=W6aKQ-eBFk0 https://www.youtube.com/watch?v=W6aKQ-eBFk0 I know why these companies do it and im lucky electricity isnt too expensive in my area but i rather shave 100 + watts of heat being dumped into my room (especially in the summer months)
ksec 3y ago
>Has anyone done a perf / watt scatterplot of the current AMD and Apple offerings? Tl;dr, if you want the absolute performance on Desktop, get the Threadripper Pro. AMD Zen 4 7800X3D, 5nm 5.04Ghz, Single Core GB6 Score @ 2833 Apple A17 Pro, 3nm 3.80Ghz, Single Core GB6 Score @ 2914 Well you can find that with Geekbench but it is very likely worst to publish it as it leads to a wrong conclusion without the basic understanding of Hardware or CPU. The node and design whether it was tuned for Clockspeed ( Desktop ) or SoC ( Apple ). There are measurable percentage difference in the same core for Risen on desktop and Ryzen SoC. And then you have to factor in Wattage difference in Clockspeed they are operating at. You are expected to know all these basics before the scatterplot would even make sense. The Desktop 7800X3D will likely use 20W+ in the test, while the Smartphone A17 uses at best 5W. You will then also have to factor it a lot of these performance test are not sustainable without adequate cooling. i.e You can sustain the above performance for a very long time on 7800X3D, dont expect that on A17 inside a phone. Many of these are pointing out the obvious. But it seems on HN we are increasingly required to do so otherwise it leads to some sort of flamewar.
bitsandboots 3y ago
Anecdotally I find my m1 laptop and ryzen 5000-series laptop to have similar energy efficiency, but I don't have much hard data. When it comes to laptops idle efficiency is king and this is where it gets hard to test the chips because the rest of the motherboard also has a role. For my m1, opening a vm or just plugging in a wireless mouse dongle is all it takes to shave several hours off the lifespan, like from 20 hours to 10. For the amd laptop, anything waking up the nvidia gpu will do the same, like 10 hours to 3. When you're talking such low amounts of power, the networking card, sound card, display efficiency, ssd efficiency, and whether the system chooses to run the fan or let the cpu stay warm starts to matter a lot since just like the cpu these are things that are running at the same time. So I guess a fair test would have to use the same ssd and have the monitor off, using an external monitor. Then you're just stuck with the efficiency of the parts of the motherboard you can't choose.

by hedora 3y ago

maccard 3y ago

I have an older threadripper - a 3970x. It's the most power hungry device in my house after my electric oven. In raw numbers it's hard to beat. But it is _not_ efficient

hamandcheese 3y ago
That is now a two generation old CPU at this point - I don't think we started seeing AMD get competitive on power efficiency until Zen 3.
jrockway 3y ago
I have the same chip and it's amazing to see it idle at 75W after growing up on Intel chips that use like 5W at idle. Of note is that Zen 2 (the 3970x's microarchitecture) is 7nm. The new Threadrippers are on a 5nm process. I would expect slightly lower power consumption, but note that the 7000 series of Threadrippers quote a TDP of 350W while the 3000 series quote 280W. So I'm guessing they're using the efficiency for more speed instead of more power savings. To me, it's fine. I'd always prefer paying more for electricity than to wait longer for something to complete. (But I do respect the desktop chips that can blink my cursor with an efficiency core that uses a few tens of milliwatts.)
dathinab 3y ago
Zen 4 is known to be noticeable more efficient then Zen 3 and even much much more so then Zen 2 so I don't think this comparison is helpful.
pleoxy 3y ago
All of the AMD chiplet based designs do poorly at idle power. These monsters will do better than the 39xx because of the 6mm IO die. But it's still going to have high idle power compared to a monolithic Intel design. The monolithic AMD dies (laptop/mobile) are competitive in the idle power space.

protastus 3y ago

I have a 16-core Ryzen 7950X that I run in "eco mode 105W". This delivers performance close to an Intel 13900K but at less than half the power. It's also much easier to cool and get a quiet PC without water cooling and enthusiast shenanigans (de-lidding, etc.) I don't know if the Zen 4 Threadrippers can be similarly run with a power limit. If they can, I'd expect much better efficiency than whatever Intel offers. This has eco mode benchmarks: https://youtu.be/W6aKQ-eBFk0?si=o8l1qGUhSQKxmY_c https://youtu.be/W6aKQ-eBFk0?si=o8l1qGUhSQKxmY_c

kcb 3y ago

Surprisingly haven't found great comparisons. A 7840U vs M2/Pro test would be pretty interesting. https://www.notebookcheck.net/R7-7840U-vs-M2_15023_14521.247596.0.html https://www.notebookcheck.net/R7-7840U-vs-M2_15023_14521.247... The last benchmark is interesting but unfair given that's an ancient application with Rosetta.

JohnTHaller 3y ago

> I'd guess this wins in absolute performance No need to guess: An M2 Ultra will get around 27,000 in Cinebench R23 while this Threadripper will get around 100,000. The M2 Ultra has a TDP around 90 watts (~ish according to a couple reviews) and this Threadripper has a TDP of 350 watts.

smolder 3y ago
There's some more nuance to efficiency than just max power at max load, of course. The Apple chips will likely have good efficiency compared to the lower core count (say, 32) TR because the watts per core gets high on those smaller TR chips. Yet if you compared their performance at a fixed 90w, I suspect the threadripper would come out ahead, since chips are much more efficient when at fractional loads that don't lead to boosted core clocks. Then again, at idle, the TR is probably guzzling power relative to the M2 Ultra. I'm only speculating to illustrate; a thorough comparison of their perf/watt characteristics would involve sampling many types of workloads of varying thread counts and levels of per-core saturation.
arp242 3y ago
If you underclock the Threadripper to get a score of ~27k, then how much power will it use? I wouldn't be surprised if it was roughly equal to 90W, or even lower. The stock configurations for a lot of desktop chips is to get the maximum performance at the expense of power, especially for things like these Threadripper series which are explicitly aimed at maximum performance. Often even drastically reducing power usage only gives modest performance penalties.
- mafuy 3y ago
  Yes, cutting power targets of a (Desktop) Ryzen to 65W or 90W reduces performance to around 50% or 80% in some benchmarks, iirc. Likely a good tradeoff in many scenarios. I also run an RTX 3900 GPU at 60% power for 80-90% performance. It's a noticeable decrease in requisite cooling.
- mrbigbob 3y ago
  Yeah I am definitely not a fan of Intel/AMD/and even Nvidia who will completely push power to stupid levels just to get less than an extra 10% performance Gamers Nexus did a video earlier this year comparing the 7950x at different eco modes and they found that putting the 7950x at a 105 watt eco made drop the performance around 5% but shaved almost 100 watts off of power. heres the link to the video https://www.youtube.com/watch?v=W6aKQ-eBFk0 https://www.youtube.com/watch?v=W6aKQ-eBFk0 I know why these companies do it and im lucky electricity isnt too expensive in my area but i rather shave 100 + watts of heat being dumped into my room (especially in the summer months)

ksec 3y ago

>Has anyone done a perf / watt scatterplot of the current AMD and Apple offerings? Tl;dr, if you want the absolute performance on Desktop, get the Threadripper Pro. AMD Zen 4 7800X3D, 5nm 5.04Ghz, Single Core GB6 Score @ 2833 Apple A17 Pro, 3nm 3.80Ghz, Single Core GB6 Score @ 2914 Well you can find that with Geekbench but it is very likely worst to publish it as it leads to a wrong conclusion without the basic understanding of Hardware or CPU. The node and design whether it was tuned for Clockspeed ( Desktop ) or SoC ( Apple ). There are measurable percentage difference in the same core for Risen on desktop and Ryzen SoC. And then you have to factor in Wattage difference in Clockspeed they are operating at. You are expected to know all these basics before the scatterplot would even make sense. The Desktop 7800X3D will likely use 20W+ in the test, while the Smartphone A17 uses at best 5W. You will then also have to factor it a lot of these performance test are not sustainable without adequate cooling. i.e You can sustain the above performance for a very long time on 7800X3D, dont expect that on A17 inside a phone. Many of these are pointing out the obvious. But it seems on HN we are increasingly required to do so otherwise it leads to some sort of flamewar.

bitsandboots 3y ago

Anecdotally I find my m1 laptop and ryzen 5000-series laptop to have similar energy efficiency, but I don't have much hard data. When it comes to laptops idle efficiency is king and this is where it gets hard to test the chips because the rest of the motherboard also has a role. For my m1, opening a vm or just plugging in a wireless mouse dongle is all it takes to shave several hours off the lifespan, like from 20 hours to 10. For the amd laptop, anything waking up the nvidia gpu will do the same, like 10 hours to 3. When you're talking such low amounts of power, the networking card, sound card, display efficiency, ssd efficiency, and whether the system chooses to run the fan or let the cpu stay warm starts to matter a lot since just like the cpu these are things that are running at the same time. So I guess a fair test would have to use the same ssd and have the monitor off, using an external monitor. Then you're just stuck with the efficiency of the parts of the motherboard you can't choose.