23 ms·

MacBook Pro throttling not a CPU issue, but rather power throttling of the VRM

151 points by nthuser 8y ago

vesrah 8y ago
Originally posted at MacRumors by winterny https://forums.macrumors.com/threads/optimal-cpu-tuning-settings-for-i9-mbp-to-stop-vrm-throttling-explanation-of-apples-engineering-f.2128936/ https://forums.macrumors.com/threads/optimal-cpu-tuning-sett...
- dang 8y ago
  Thanks! Url changed from https://old.reddit.com/r/macbookpro/comments/91256u/optimal_cpu_tuning_settings_for_i9_mbp_to_stop/ https://old.reddit.com/r/macbookpro/comments/91256u/optimal_..., which straight-up copies this.
  - DuskStar 8y ago
    I think it's the other way around - MacRumors post was July 22nd at 4:57pm while the Reddit post was July 22nd at 4:36pm GMT-7. (I can't tell if I'm being messed up by time zones though as that doesn't appear on mouseover for MacRumors)
    - dang 8y ago
      Ah ok. Changed back from https://forums.macrumors.com/threads/optimal-cpu-tuning-settings-for-i9-mbp-to-stop-vrm-throttling-explanation-of-apples-engineering-f.2128936/ https://forums.macrumors.com/threads/optimal-cpu-tuning-sett.... Sorry!
- sp332 8y ago
  An update from the Reddit comment that's not on the first page of the macrumors thread: [Edited to add note: From messages others have sent me, it seems that this MSR is actually not Intel's default, but rather this is what Apple has been setting the MSR value to on all intel chips in Macbook Pro and Macbook Air for a number of years ... This is just the first chip to actually be capable of drawing enough power for this to matter. Previous chips just couldn't draw that much power, so they never hit the VRM limit before]
dugditches 8y ago
Seems crazy to spend so much on a machine, just have to do something that apparently can void your warranty if something goes amiss, to take advantage of the extra power you paid for.
- sp332 8y ago
  Well, they do claim to have a firmware fix. https://arstechnica.com/gadgets/2018/07/we-tested-throttling-on-the-macbook-pro-now-apple-says-it-has-a-firmware-fix/ https://arstechnica.com/gadgets/2018/07/we-tested-throttling...
slededit 8y ago
That is much more embarrassing than simple thermal throttling of the CPU. The thermal overload on PMIC chips are designed to handle malfunctions not regular usage.
- stefan_ 8y ago
  If the voltage regulator is overheating at high CPU load, it must be getting very hot at just normal load. That will seriously reduce it's life span, not to mention a hot voltage regulator means you're pissing away battery unnecessarily.
- GeekyBear 8y ago
  This is the same issue the current Dell XPS 15 has when running a mainstream i7. https://www.ultrabookreview.com/14875-fix-throttling-xps-15/ https://www.ultrabookreview.com/14875-fix-throttling-xps-15/
simooooo 8y ago
Phantom throttling has been a big issue in the desktop i9s too. I've ran into it overclock mine many times.
no1youknowz 8y ago
On TWiT[0]. They had the keyboard up to 115f sometimes, some other videos on youtube have gone much higher. I've also seen a couple of youtubers and the number is growing, returning their macbooks [1], [2], due to the performance and the number is growing daily. I really think this issue is down to a few things. 1) The need from Apple to be thinner each iteration, is really costing them the ability to have better thermals and fans. 2) Putting an 14nm chip where a 10nm should be. Unfortunately Intel is having issues with that. 3) No vents at the sides or the back, only where the screen is. Poor design considerations when it comes to heat. I'm going to be keeping onto my MBPr 2012 for another year. I want to see some of these issues being resolved. I would not be surprised if this spurs on Apple to phase in Arm processors in 2020. [0]: https://www.youtube.com/watch?v=6DcIP6FtuRk https://www.youtube.com/watch?v=6DcIP6FtuRk [1]: https://www.youtube.com/watch?v=aZfXBN6kqu8 https://www.youtube.com/watch?v=aZfXBN6kqu8 [2]: https://www.youtube.com/watch?v=l_K1rpYz6ug https://www.youtube.com/watch?v=l_K1rpYz6ug
- slantyyz 8y ago
  Also worth watching: Louis Rossman posted his thoughts on this Reddit post as well: https://www.youtube.com/watch?v=Xjor24HO2HA https://www.youtube.com/watch?v=Xjor24HO2HA
- rm_-rf_slash 8y ago
  Similarly, my 2012 Air (8gb RAM, 500gb SSD) is working just fine, and I could probably get quite a few more years out of it. It astonishes me how well that old laptop does what I need, considering any laptop from 2006 or 2004 would have been slow as molasses in 2012, and total garbage today.
  - tzahola 8y ago
    Moore’s law is over.
  - deleted 8y ago
    [deleted]
  - basch 8y ago
baybal2 8y ago
All powerfull cpus and gpus these days have what is called droop detection. When they detect undervoltage, they "stretch" the master clock. Effectively, they skip clock cycles till voltage recovers in power supply capacitors.
fhood 8y ago
I don't understand how this happened. Apple is a company that built it's empire on paying a premium for reliability and ease of use. There have been mistakes in the past, but this is something that should have been caught immediately, which suggests that they were aware of it at release. Is it just nostalgia goggles telling me that Jobs would not have let these out the door?
- opencl 8y ago
  The Apple III had a 100% failure rate because Steve Jobs personally insisted that it have neither cooling fans nor vents.
  - hyper2grams 8y ago
    So they're truly living up to his legacy.
- slantyyz 8y ago
  While Apple's not blameless in the matter, this seems to be more of an Intel issue no? It appears the i9 isn't a good fit for thin and light laptops (Apple's also not the only one using the i9 in this form factor). Of course, a laptop using this i9 and properly cooling it is not going to be small or pretty[1]. Getting back to Apple, there are a couple of ways of looking at this. For people who are bursting (as opposed to doing long running sustained loads) the i9 is probably the fastest Macbook Pro you can get. For people who are using optimized media apps like FCP, this is also not necessarily a bad buy, since you'll likely reap the benefits of the faster CPU. For people who are doing sustained loads and/or running non-optimized apps like Premiere, this is probably not a good Macbook Pro to buy. For people who care a lot about getting advertised baseline clock rates, irrespective of bottom line performance gains, this is also not the Macbook Pro to buy. For some, it's an easy choice, and for others, it's complicated. [1] https://www.youtube.com/watch?v=xeUlGnNUut8 https://www.youtube.com/watch?v=xeUlGnNUut8
  - ubercore 8y ago
    > While Apple's not blameless in the matter, this seems to be more of an Intel issue no? I mean, Apple sourced the chip and shipped the laptop, and you pay Apple. I don't see how you _can't_ blame Apple engineering for this?
akulbe 8y ago
It looks like Apple has already released a software update to fix this.
xchaotic 8y ago
Such delays in shipping and yet the hardware designs are rushed. I'm switching to Linux laptop with 64GB RAM. There might be some pain for a bit, but IMO totally worth it for Apple to have viable competition in the 'pro' space.
- kristianp 8y ago
  What laptop are you getting?
evadne 8y ago
Apple statement: Following extensive performance testing under numerous workloads, we've identified that there is a missing digital key in the firmware that impacts the thermal management system and could drive clock speeds down under heavy thermal loads on the new MacBook Pro. https://forums.macrumors.com/threads/apple-addresses-macbook-pro-throttling-controversy-after-working-with-youtuber-dave-lee.2129221/ https://forums.macrumors.com/threads/apple-addresses-macbook...
post_break 8y ago
Apple put out a patch it looks like: https://www.macrumors.com/2018/07/24/apple-addresses-macbook-pro-throttling/ https://www.macrumors.com/2018/07/24/apple-addresses-macbook...
satysin 8y ago
I got my 15" 2.6Ghz i7 model yesterday and I love it. Obviously there are issues as many have reported but I am using this for iOS and Android development and this thing is a good 30-45% faster for builds compared to my top-spec 2017 model. The Android emulator starts up (cold boot not from save state) faster as well (just measured it at 9 seconds to boot a Nexus 5X API 28 AVD vs 16 seconds on my 2017 i7). Once things have settled down a bit I will look into things again but I am in no rush to start modifying firmware values when, for my needs, everything is great. For those interested the new keyboard is a little "softer" and quieter. My wife commented on how different it sounds. I would say it sound similar to a Dell XPS 15 or ThinkPad T480 in terms of how loud it is. The TrueTone option for the display is lovely for programming imho. Really nice little new feature. Other than that not much has changed externally though. It is still a very nice machine and I hope Apple tweaks things to address the thermal throttling people are seeing. For development though it is a dream. Edit: Seems Apple has released an update to fix this https://news.ycombinator.com/item?id=17603063 https://news.ycombinator.com/item?id=17603063
- Exuma 8y ago
  Have you used Butterfly v.1 to compare it to? I absolutely hated v.1 with a passion (it's like typing on a flat desk), I absolutely LOVED v.2 with a passion. I'm wondering how I will like v.3...
  - satysin 8y ago
    Yes I have used all 3 butterfly keyboards. I agree the first gen was awful. 2nd felt great but was quite loud[0] and had the issues with dust obviously. This is very much like 2nd gen with just a very very subtle softness to it. It feels really to me. I think if you love 2nd you will love 3rd even more. [0] The whole "omg it is so loud!!!" thing kind of made me laugh as everyone that I knew who made such a complaint had a mech keyboard with some obnoxiously loud cherry mx switch in it. I mean yes I did feel the 1st and 2nd gen butterfly keyboards were too loud but they were still quieter than any mech keyboard I have used!
    - Exuma 8y ago
frou_dh 8y ago
Insisting on using the same chassis design for i9, dGPU packin' models is like a person not having a summer wardrobe and inappropriately wearing winter clothes all year round. It ain't clever and people are going to notice.
jiveturkey 8y ago
oy. now i'm really torn. i canceled my i9 order and placed an i7 order instead. i will relatively rarely need peak performance but when i do, it's in work stretches long enough that i want absolute best performance. it has to be on the same laptop -- i cannot offload to a desktop or another machine. now, do i cancel the i7 and re-order the i9? argh. it's painful to just delay my order for a month, knowing a much higher performing laptop is available now. i'm inclined to keep the i7 as i understand from one of the many vids that the "normal" operating temperature is much lower. even on my older i5, i am very sensitive to the keyboard getting hot.

151 points by nthuser 8y ago

Originally posted at MacRumors by winterny https://forums.macrumors.com/threads/optimal-cpu-tuning-settings-for-i9-mbp-to-stop-vrm-throttling-explanation-of-apples-engineering-f.2128936/ https://forums.macrumors.com/threads/optimal-cpu-tuning-sett...

dang 8y ago
Thanks! Url changed from https://old.reddit.com/r/macbookpro/comments/91256u/optimal_cpu_tuning_settings_for_i9_mbp_to_stop/ https://old.reddit.com/r/macbookpro/comments/91256u/optimal_..., which straight-up copies this.
- DuskStar 8y ago
  I think it's the other way around - MacRumors post was July 22nd at 4:57pm while the Reddit post was July 22nd at 4:36pm GMT-7. (I can't tell if I'm being messed up by time zones though as that doesn't appear on mouseover for MacRumors)
  - dang 8y ago
    Ah ok. Changed back from https://forums.macrumors.com/threads/optimal-cpu-tuning-settings-for-i9-mbp-to-stop-vrm-throttling-explanation-of-apples-engineering-f.2128936/ https://forums.macrumors.com/threads/optimal-cpu-tuning-sett.... Sorry!
sp332 8y ago
An update from the Reddit comment that's not on the first page of the macrumors thread: [Edited to add note: From messages others have sent me, it seems that this MSR is actually not Intel's default, but rather this is what Apple has been setting the MSR value to on all intel chips in Macbook Pro and Macbook Air for a number of years ... This is just the first chip to actually be capable of drawing enough power for this to matter. Previous chips just couldn't draw that much power, so they never hit the VRM limit before]

dugditches 8y ago

Seems crazy to spend so much on a machine, just have to do something that apparently can void your warranty if something goes amiss, to take advantage of the extra power you paid for.

sp332 8y ago
Well, they do claim to have a firmware fix. https://arstechnica.com/gadgets/2018/07/we-tested-throttling-on-the-macbook-pro-now-apple-says-it-has-a-firmware-fix/ https://arstechnica.com/gadgets/2018/07/we-tested-throttling...

slededit 8y ago

That is much more embarrassing than simple thermal throttling of the CPU. The thermal overload on PMIC chips are designed to handle malfunctions not regular usage.

stefan_ 8y ago
If the voltage regulator is overheating at high CPU load, it must be getting very hot at just normal load. That will seriously reduce it's life span, not to mention a hot voltage regulator means you're pissing away battery unnecessarily.
GeekyBear 8y ago
This is the same issue the current Dell XPS 15 has when running a mainstream i7. https://www.ultrabookreview.com/14875-fix-throttling-xps-15/ https://www.ultrabookreview.com/14875-fix-throttling-xps-15/

simooooo 8y ago

Phantom throttling has been a big issue in the desktop i9s too. I've ran into it overclock mine many times.

no1youknowz 8y ago

On TWiT[0]. They had the keyboard up to 115f sometimes, some other videos on youtube have gone much higher. I've also seen a couple of youtubers and the number is growing, returning their macbooks [1], [2], due to the performance and the number is growing daily. I really think this issue is down to a few things. 1) The need from Apple to be thinner each iteration, is really costing them the ability to have better thermals and fans. 2) Putting an 14nm chip where a 10nm should be. Unfortunately Intel is having issues with that. 3) No vents at the sides or the back, only where the screen is. Poor design considerations when it comes to heat. I'm going to be keeping onto my MBPr 2012 for another year. I want to see some of these issues being resolved. I would not be surprised if this spurs on Apple to phase in Arm processors in 2020. [0]: https://www.youtube.com/watch?v=6DcIP6FtuRk https://www.youtube.com/watch?v=6DcIP6FtuRk [1]: https://www.youtube.com/watch?v=aZfXBN6kqu8 https://www.youtube.com/watch?v=aZfXBN6kqu8 [2]: https://www.youtube.com/watch?v=l_K1rpYz6ug https://www.youtube.com/watch?v=l_K1rpYz6ug

slantyyz 8y ago
Also worth watching: Louis Rossman posted his thoughts on this Reddit post as well: https://www.youtube.com/watch?v=Xjor24HO2HA https://www.youtube.com/watch?v=Xjor24HO2HA
rm_-rf_slash 8y ago
Similarly, my 2012 Air (8gb RAM, 500gb SSD) is working just fine, and I could probably get quite a few more years out of it. It astonishes me how well that old laptop does what I need, considering any laptop from 2006 or 2004 would have been slow as molasses in 2012, and total garbage today.
- tzahola 8y ago
  Moore’s law is over.
- deleted 8y ago
  [deleted]
- basch 8y ago

baybal2 8y ago

All powerfull cpus and gpus these days have what is called droop detection. When they detect undervoltage, they "stretch" the master clock. Effectively, they skip clock cycles till voltage recovers in power supply capacitors.

fhood 8y ago

I don't understand how this happened. Apple is a company that built it's empire on paying a premium for reliability and ease of use. There have been mistakes in the past, but this is something that should have been caught immediately, which suggests that they were aware of it at release. Is it just nostalgia goggles telling me that Jobs would not have let these out the door?

opencl 8y ago
The Apple III had a 100% failure rate because Steve Jobs personally insisted that it have neither cooling fans nor vents.
- hyper2grams 8y ago
  So they're truly living up to his legacy.
slantyyz 8y ago
While Apple's not blameless in the matter, this seems to be more of an Intel issue no? It appears the i9 isn't a good fit for thin and light laptops (Apple's also not the only one using the i9 in this form factor). Of course, a laptop using this i9 and properly cooling it is not going to be small or pretty[1]. Getting back to Apple, there are a couple of ways of looking at this. For people who are bursting (as opposed to doing long running sustained loads) the i9 is probably the fastest Macbook Pro you can get. For people who are using optimized media apps like FCP, this is also not necessarily a bad buy, since you'll likely reap the benefits of the faster CPU. For people who are doing sustained loads and/or running non-optimized apps like Premiere, this is probably not a good Macbook Pro to buy. For people who care a lot about getting advertised baseline clock rates, irrespective of bottom line performance gains, this is also not the Macbook Pro to buy. For some, it's an easy choice, and for others, it's complicated. [1] https://www.youtube.com/watch?v=xeUlGnNUut8 https://www.youtube.com/watch?v=xeUlGnNUut8
- ubercore 8y ago
  > While Apple's not blameless in the matter, this seems to be more of an Intel issue no? I mean, Apple sourced the chip and shipped the laptop, and you pay Apple. I don't see how you _can't_ blame Apple engineering for this?

akulbe 8y ago

It looks like Apple has already released a software update to fix this.

xchaotic 8y ago

Such delays in shipping and yet the hardware designs are rushed. I'm switching to Linux laptop with 64GB RAM. There might be some pain for a bit, but IMO totally worth it for Apple to have viable competition in the 'pro' space.

kristianp 8y ago
What laptop are you getting?

evadne 8y ago

Apple statement: Following extensive performance testing under numerous workloads, we've identified that there is a missing digital key in the firmware that impacts the thermal management system and could drive clock speeds down under heavy thermal loads on the new MacBook Pro. https://forums.macrumors.com/threads/apple-addresses-macbook-pro-throttling-controversy-after-working-with-youtuber-dave-lee.2129221/ https://forums.macrumors.com/threads/apple-addresses-macbook...

post_break 8y ago

Apple put out a patch it looks like: https://www.macrumors.com/2018/07/24/apple-addresses-macbook-pro-throttling/ https://www.macrumors.com/2018/07/24/apple-addresses-macbook...

satysin 8y ago

I got my 15" 2.6Ghz i7 model yesterday and I love it. Obviously there are issues as many have reported but I am using this for iOS and Android development and this thing is a good 30-45% faster for builds compared to my top-spec 2017 model. The Android emulator starts up (cold boot not from save state) faster as well (just measured it at 9 seconds to boot a Nexus 5X API 28 AVD vs 16 seconds on my 2017 i7). Once things have settled down a bit I will look into things again but I am in no rush to start modifying firmware values when, for my needs, everything is great. For those interested the new keyboard is a little "softer" and quieter. My wife commented on how different it sounds. I would say it sound similar to a Dell XPS 15 or ThinkPad T480 in terms of how loud it is. The TrueTone option for the display is lovely for programming imho. Really nice little new feature. Other than that not much has changed externally though. It is still a very nice machine and I hope Apple tweaks things to address the thermal throttling people are seeing. For development though it is a dream. Edit: Seems Apple has released an update to fix this https://news.ycombinator.com/item?id=17603063 https://news.ycombinator.com/item?id=17603063

Exuma 8y ago
Have you used Butterfly v.1 to compare it to? I absolutely hated v.1 with a passion (it's like typing on a flat desk), I absolutely LOVED v.2 with a passion. I'm wondering how I will like v.3...
- satysin 8y ago
  Yes I have used all 3 butterfly keyboards. I agree the first gen was awful. 2nd felt great but was quite loud[0] and had the issues with dust obviously. This is very much like 2nd gen with just a very very subtle softness to it. It feels really to me. I think if you love 2nd you will love 3rd even more. [0] The whole "omg it is so loud!!!" thing kind of made me laugh as everyone that I knew who made such a complaint had a mech keyboard with some obnoxiously loud cherry mx switch in it. I mean yes I did feel the 1st and 2nd gen butterfly keyboards were too loud but they were still quieter than any mech keyboard I have used!
  - Exuma 8y ago

frou_dh 8y ago

Insisting on using the same chassis design for i9, dGPU packin' models is like a person not having a summer wardrobe and inappropriately wearing winter clothes all year round. It ain't clever and people are going to notice.

jiveturkey 8y ago

oy. now i'm really torn. i canceled my i9 order and placed an i7 order instead. i will relatively rarely need peak performance but when i do, it's in work stretches long enough that i want absolute best performance. it has to be on the same laptop -- i cannot offload to a desktop or another machine. now, do i cancel the i7 and re-order the i9? argh. it's painful to just delay my order for a month, knowing a much higher performing laptop is available now. i'm inclined to keep the i7 as i understand from one of the many vids that the "normal" operating temperature is much lower. even on my older i5, i am very sensitive to the keyboard getting hot.