9 ms·

I'm confused. I easily get 8-10 hours on my Core i7 laptop as long as I'm not at 100% CPU usage permanently. Modern Ryzens also hit this easily. So I don't know

by Zevis 5y ago

I'm confused. I easily get 8-10 hours on my Core i7 laptop as long as I'm not at 100% CPU usage permanently. Modern Ryzens also hit this easily. So I don't know why 8 hours screen on time on a tiny screen with an incomparably weak CPU is supposed to be proof of how much we need ARM. Apple's M1 is in a class of its own, unfortunately.

PragmaticPulp 5y ago
I’m also frequently confused when people refer to Windows laptops as in a different league of battery life. Modern Windows laptops do just fine. M1 is a cycle ahead, but the Ryzen mobile parts are actually very good too.
- Roritharr 5y ago
  I suspect it has todo with getting decked out machines. If you've got the >1tb ssd and the >=32GB RAM model, you will see your OS simply use the ressources for caching and speeding up the machine, which in turn will use more battery. At least that's my pet theory, running an 4750U with 64GB of RAM installed ;)
  - saltcured 5y ago
    The RAM probably uses more power just by having more installed, but it shouldn't be causing more expensive work. If anything, being able to use RAM cached content should allow the SSD and its IO channels to idle more often. A "decked out" laptop might also have a more powerful GPU with nowhere near as good idle power characteristics. But, the largest differences are probably in idle power management, with the phone having much lower power IO channels and better zoned power management to really reduce idle power. A laptop often has the system in a much higher power level with off-chip resources powered up, including WiFi, screen refresh, data buses, and backlight driving a much larger screen area. Edit to add: I've noticed on laptops with Linux that vastly different battery life from "similar" machines come from differences in how the software and firmware interact to reach different powersaving modes for screen on but idle states, such as with a browser open on a page that has already rendered and awaits user input.
    - vlovich123 5y ago
      That’s not quite accurate. When you’re talking about standby time in suspend-to-ram, RAM refresh is actually a non-trivial battery cost because it’s basically you’re only active power draw remaining. Which DIMMs have active memory pages is a partial function of memory usage. So if your kernel woke up (let’s say after 30 min of suspend to ram) to try and see if it can reclaim physical DIMMs and mark them unused (shrink caches, reorganize pages, etc) you could get quite a big win on standby time. The trick is how to do this without actually hurting battery life (waking up can be expensive and there’s no guarantee you’ll be able to free up DIMMs) and preserving wake from suspend performance (if you’re phone is laggy on wake that’s an experience users will switch away from + you could eat your entire power savings paging back in).
      - formerly_proven 5y ago
        Is the memory controller aware of unused pages in physical RAM that thus can be safely skipped during refresh? That would surprise me. In stand-by the self-refresh mode is used, and I believe partial refresh is only supported by the low-power (LPDDRx) standards and is very coarse-grained.
        vlovich123 5y ago
        No. What I heard proposed was just at the DIMM level. The memory controller has no concept of memory usage.
      - saltcured 5y ago
        The refresh costs you are talking about are what I meant by the RAM has cost by being installed on a typical laptop. The power is used because the machine is in an active-idle power state with that much RAM installed, not because the OS has decided to burn more CPU time in the presence of more RAM as someone suggested earlier in the chain. Most of the idle power consumption is all the ancillary system controllers, not the CPU cores themselves. These are the things that are better managed on a typical smartphone SoC platform. And, I am referring to active idle, not suspend-to-ram scenarios. I think people are talking about screen-on time for battery life, not lid closed and suspended nor lid open but screen disabled. Precious few people are enjoying a laptop that successfully performs a suspend to RAM sleep state while keeping the display alive. Often, the integrated GPU is continuously scanning framebuffers in system RAM and outputting pixel data to the embedded display port even though nothing is changing on screen. Frequently, drivers have disabled LCD panel self refresh modes due to unresolved glitches and artifacts in the graphics stack.
- rtpg 5y ago
  Lots of people buy 15 inchers with dedicated graphics etc. Or like... run Linux (which hoses the battery on a lot of stuff if you just use it out of the box without tweaking stuff). Also really cheap laptops aren't as great about battery life just cuz of reasons. I think there's a lot of selection bias (like people who have a lot of money will buy macbooks in general cuz that's what everyone says to do)
  - tachyonbeam 5y ago
    Why isn't Linux configured to better preserve battery life on laptops by default? Power usage has been an issue for over a decade. If it's just a matter of a few tweaks, surely it could be done?
    - rtpg 5y ago
      Mostly speculation, but I think a big part of it is that MacOS will heavily throttle as it needs to, and I imagine that Windows laptop drivers get a lot of love in that space too since the manufacturers want to get good battery life in their machines as well. I'm sure a huge component of it is just people-hours spent in figuring out the right balance of defaults that don't just mess people's setups up.
    - wtallis 5y ago
      It's not a matter of just a few tweaks. It's a few new tweaks each generation, as Microsoft and Intel keep changing their minds on what the "right" way is to put devices into low-power modes, and then not thoroughly documenting those changes let alone upstream them for inclusion in standards documents. And then there are the hardware bugs which require workarounds in firmware or drivers, and the firmware bugs which require workarounds in drivers, all of which are only developed and tested against Windows. The set of power management options that Windows 10 exposes to the user has been steadily dwindling to the point that on a new laptop you basically only get to customize how long before the screen shuts off and how long before it goes to sleep. All the more detailed options you had in early Windows 10 or in Windows 7 are no longer exposed, because there's no consistent way to map such controls onto the ever-shifting set of underlying platform features.
- p_l 5y ago
  It's a reality distortion field and maybe effect of not blocking OSX's default "go to sleep the moment you stop looking at it" policy. Macs were stuck at (marketing) 10h battery lifetime for so long (for comparison - Xeon mobile workstations with few times the power regularly hit 10h on battery without tuning), that M1 feels like huge jump out of nowhere.
systemvoltage 5y ago
> Apple's M1 is in a class of its own, unfortunately. We want companies to excel and give a stiff competition to their peers. Now that we have M1, it's pushing the entire floor to the next level - pushing Intel, AMD and the entire x86 ecosystem. Curious, why do you think it's unfortunate? Is it because Apple is a large company?
- dannyw 5y ago
  Not OP, but Apple doesn't sell their chips to other companies. It's their right to do so, but if Apple sold M1, that'd be great for consumers.
  - f6v 5y ago
    M1 is that good because Apple customises their software for it(or the other way around). I doubt any other company would dedicate that much effort to it.
    - saagarjha 5y ago
      M1 is quite good at general-purpose workloads.
- duskwuff 5y ago
  Not the parent, but: it isn't unfortunate that the M1 is so good; it's unfortunate that everything else is so far behind.
  - jeswin 5y ago
    Is it that far behind? Benchmarks aren't everything, but it's probably as good as other metrics. A14 is ahead of SD888 in Geekbench (which has historically favored Apple CPUs), and behind on Antutu (which is more considerate to Snapdragons). Geekbench 5: - Single core: A14 1609, SD888 1127 - Multi core: A14 3872, SD888 3731 Antutu: - A14 615796, SD888 723674
    - 5y ago
f6v 5y ago
I was considering Zephyrus G14 at some point, so I visited the dedicated subreddit. There was a guide on getting it to ~8 hrs on battery. Man, I lost my enthusiasm right away. Custom fan management, getting rid of bloatware...
ajross 5y ago
Yeah. Consumer CPU power draw is largely a solved problem. Total aggregate processor energy use on a typical Intel laptop is already down to somewhere around 20-30% of what the display backlight pulls. That's good enough, you're just not going to do much better on a laptop form factor. The M1 isn't really that notable for "battery life", it isn't. All the people raving are people hitting particular edge cases of high CPU utilization that consumers (even developers) generally don't see when browsing and watching. The Apple power magic is all happening in phones. And the magic of the M1 is that they have achieved desktop-class (nearly market-leading) performance in a chip that still draws like a phone at idle. It's an amazing piece of engineering, but in a laptop it's really just an incremental improvement over what we already have.
fulafel 5y ago
Does the processor really dominate power consumption in modern laptops so much that the M1 chip largely explains the long battery life in new Macbooks? The data doesn't seem easy to come by with a cursory web search.

by Zevis 5y ago

PragmaticPulp 5y ago

I’m also frequently confused when people refer to Windows laptops as in a different league of battery life. Modern Windows laptops do just fine. M1 is a cycle ahead, but the Ryzen mobile parts are actually very good too.

Roritharr 5y ago
I suspect it has todo with getting decked out machines. If you've got the >1tb ssd and the >=32GB RAM model, you will see your OS simply use the ressources for caching and speeding up the machine, which in turn will use more battery. At least that's my pet theory, running an 4750U with 64GB of RAM installed ;)
- saltcured 5y ago
  The RAM probably uses more power just by having more installed, but it shouldn't be causing more expensive work. If anything, being able to use RAM cached content should allow the SSD and its IO channels to idle more often. A "decked out" laptop might also have a more powerful GPU with nowhere near as good idle power characteristics. But, the largest differences are probably in idle power management, with the phone having much lower power IO channels and better zoned power management to really reduce idle power. A laptop often has the system in a much higher power level with off-chip resources powered up, including WiFi, screen refresh, data buses, and backlight driving a much larger screen area. Edit to add: I've noticed on laptops with Linux that vastly different battery life from "similar" machines come from differences in how the software and firmware interact to reach different powersaving modes for screen on but idle states, such as with a browser open on a page that has already rendered and awaits user input.
  - vlovich123 5y ago
    That’s not quite accurate. When you’re talking about standby time in suspend-to-ram, RAM refresh is actually a non-trivial battery cost because it’s basically you’re only active power draw remaining. Which DIMMs have active memory pages is a partial function of memory usage. So if your kernel woke up (let’s say after 30 min of suspend to ram) to try and see if it can reclaim physical DIMMs and mark them unused (shrink caches, reorganize pages, etc) you could get quite a big win on standby time. The trick is how to do this without actually hurting battery life (waking up can be expensive and there’s no guarantee you’ll be able to free up DIMMs) and preserving wake from suspend performance (if you’re phone is laggy on wake that’s an experience users will switch away from + you could eat your entire power savings paging back in).
    - formerly_proven 5y ago
      Is the memory controller aware of unused pages in physical RAM that thus can be safely skipped during refresh? That would surprise me. In stand-by the self-refresh mode is used, and I believe partial refresh is only supported by the low-power (LPDDRx) standards and is very coarse-grained.
      - vlovich123 5y ago
        No. What I heard proposed was just at the DIMM level. The memory controller has no concept of memory usage.
    - saltcured 5y ago
      The refresh costs you are talking about are what I meant by the RAM has cost by being installed on a typical laptop. The power is used because the machine is in an active-idle power state with that much RAM installed, not because the OS has decided to burn more CPU time in the presence of more RAM as someone suggested earlier in the chain. Most of the idle power consumption is all the ancillary system controllers, not the CPU cores themselves. These are the things that are better managed on a typical smartphone SoC platform. And, I am referring to active idle, not suspend-to-ram scenarios. I think people are talking about screen-on time for battery life, not lid closed and suspended nor lid open but screen disabled. Precious few people are enjoying a laptop that successfully performs a suspend to RAM sleep state while keeping the display alive. Often, the integrated GPU is continuously scanning framebuffers in system RAM and outputting pixel data to the embedded display port even though nothing is changing on screen. Frequently, drivers have disabled LCD panel self refresh modes due to unresolved glitches and artifacts in the graphics stack.
rtpg 5y ago
Lots of people buy 15 inchers with dedicated graphics etc. Or like... run Linux (which hoses the battery on a lot of stuff if you just use it out of the box without tweaking stuff). Also really cheap laptops aren't as great about battery life just cuz of reasons. I think there's a lot of selection bias (like people who have a lot of money will buy macbooks in general cuz that's what everyone says to do)
- tachyonbeam 5y ago
  Why isn't Linux configured to better preserve battery life on laptops by default? Power usage has been an issue for over a decade. If it's just a matter of a few tweaks, surely it could be done?
  - rtpg 5y ago
    Mostly speculation, but I think a big part of it is that MacOS will heavily throttle as it needs to, and I imagine that Windows laptop drivers get a lot of love in that space too since the manufacturers want to get good battery life in their machines as well. I'm sure a huge component of it is just people-hours spent in figuring out the right balance of defaults that don't just mess people's setups up.
  - wtallis 5y ago
    It's not a matter of just a few tweaks. It's a few new tweaks each generation, as Microsoft and Intel keep changing their minds on what the "right" way is to put devices into low-power modes, and then not thoroughly documenting those changes let alone upstream them for inclusion in standards documents. And then there are the hardware bugs which require workarounds in firmware or drivers, and the firmware bugs which require workarounds in drivers, all of which are only developed and tested against Windows. The set of power management options that Windows 10 exposes to the user has been steadily dwindling to the point that on a new laptop you basically only get to customize how long before the screen shuts off and how long before it goes to sleep. All the more detailed options you had in early Windows 10 or in Windows 7 are no longer exposed, because there's no consistent way to map such controls onto the ever-shifting set of underlying platform features.
p_l 5y ago
It's a reality distortion field and maybe effect of not blocking OSX's default "go to sleep the moment you stop looking at it" policy. Macs were stuck at (marketing) 10h battery lifetime for so long (for comparison - Xeon mobile workstations with few times the power regularly hit 10h on battery without tuning), that M1 feels like huge jump out of nowhere.

systemvoltage 5y ago

> Apple's M1 is in a class of its own, unfortunately. We want companies to excel and give a stiff competition to their peers. Now that we have M1, it's pushing the entire floor to the next level - pushing Intel, AMD and the entire x86 ecosystem. Curious, why do you think it's unfortunate? Is it because Apple is a large company?

dannyw 5y ago
Not OP, but Apple doesn't sell their chips to other companies. It's their right to do so, but if Apple sold M1, that'd be great for consumers.
- f6v 5y ago
  M1 is that good because Apple customises their software for it(or the other way around). I doubt any other company would dedicate that much effort to it.
  - saagarjha 5y ago
    M1 is quite good at general-purpose workloads.
duskwuff 5y ago
Not the parent, but: it isn't unfortunate that the M1 is so good; it's unfortunate that everything else is so far behind.
- jeswin 5y ago
  Is it that far behind? Benchmarks aren't everything, but it's probably as good as other metrics. A14 is ahead of SD888 in Geekbench (which has historically favored Apple CPUs), and behind on Antutu (which is more considerate to Snapdragons). Geekbench 5: - Single core: A14 1609, SD888 1127 - Multi core: A14 3872, SD888 3731 Antutu: - A14 615796, SD888 723674
  - 5y ago

f6v 5y ago

I was considering Zephyrus G14 at some point, so I visited the dedicated subreddit. There was a guide on getting it to ~8 hrs on battery. Man, I lost my enthusiasm right away. Custom fan management, getting rid of bloatware...

ajross 5y ago

Yeah. Consumer CPU power draw is largely a solved problem. Total aggregate processor energy use on a typical Intel laptop is already down to somewhere around 20-30% of what the display backlight pulls. That's good enough, you're just not going to do much better on a laptop form factor. The M1 isn't really that notable for "battery life", it isn't. All the people raving are people hitting particular edge cases of high CPU utilization that consumers (even developers) generally don't see when browsing and watching. The Apple power magic is all happening in phones. And the magic of the M1 is that they have achieved desktop-class (nearly market-leading) performance in a chip that still draws like a phone at idle. It's an amazing piece of engineering, but in a laptop it's really just an incremental improvement over what we already have.

fulafel 5y ago

Does the processor really dominate power consumption in modern laptops so much that the M1 chip largely explains the long battery life in new Macbooks? The data doesn't seem easy to come by with a cursory web search.