8 ms·

> That will help save enormous amounts of power: up to 48 percent on a single charge, Why does refresh rate have such a large impact on power consumption? I un

• perching_aix 7mo ago
  I interpreted that bit as E2E system uptime being up by 48%. Sounds more plausible to me, as there'd fewer video frames that would need to be produced and pushed out.
• blovescoffee 7mo ago
  There's definitely a few reasons but one of them is that you have to ask the GPU to do ~60x less work when you render 60x less frames
  • Filligree 7mo ago
    Why? Surely copying the same pixels out sixty times doesn't take that much power?
    • hacker_88 7mo ago
      Copying , Draw() is called 60 times a second .
      • hedora 7mo ago
        It isn't for any reasonable UI stack. For instance, the xdamage X11 extension for this was released over 20 years ago. I doubt it was the first.
        • giancarlostoro 7mo ago
          At the software level yes, but it seems nobody has taken the time to do this at the hardware level as well. This is LG's stab at it.
          • y1n0 7mo ago
            Apple has been doing this since they started having 'always-on' displays.
            • TeMPOraL 7mo ago
              So has Samsung, but we're talking mobile devices with OLED displays, which is an entirely different universe both hardware and software-wise.
        • groundzeros2015 7mo ago
          What’s your metal model of what happens when a dirty region is updated and now we need to get that buffer on the display?
        • vlovich123 7mo ago
          Xdamage isn’t a thing if you’re using a compositor for what it’s worth. It’s more expensive to try to incrementally render than to just render the entire scene (for a GPU anyway). And regardless, the HW path still involves copying the entire frame buffer - it’s literally in the name.
          • delusional 7mo ago
            Thats not true. I wrote a compositor based on xcompmgr, and there damage was widely used. It's true that it's basically pointless to do damage tracking for the final pass on gl, but damage was still useful to figure out which windows required new blurs and updated glows.
        • nottorp 7mo ago
          You forget that all modern UI toolkits brag about who has the highest frame rate, instead of updating only what's changed and only when it changes.
        • pwg 7mo ago
          It was, but xdamage is part of the composting side of the final bitmap image generation, before that final bitmap is clocked out to the display. The frame buffer, at least the portion of the GPU responsible for reading the frame buffer and shipping the contents out over the port to the display, the communications cable to the display screen itself, and the display screen were still reading, transmitting, and refreshing every pixel of the display at 60hz (or more). This LG display tech. claims to be able to turn that last portion's speed down to a 1Hz rate from whatever it usually is running at.
    • topspin 7mo ago
      The PCWorld story is trash and completely omits the key point of the new display technology, which is right in the name: "Oxide." LG has a new low-leakage thin-film transistor[1] for the display backplane. Simply, this means each pixel can hold its state longer between refreshes. So, the panel can safely drop its refresh rate to 1Hz on static content without losing the image. Yes, even "copying the same pixels" costs substantial power. There are millions of pixels with many bits each. The frame buffer has to be clocked, data latched onto buses, SERDES'ed over high-speed links to the panel drivers, and used to drive the pixels, all while making heat fighting reactance and resistance of various conductors. Dropping the entire chain to 1Hz is meaningful power savings. [1] https://news.lgdisplay.com/en/2026/03/lg-display-becomes-worlds-first-to-mass-produce-1-120hz-laptop-panel https://news.lgdisplay.com/en/2026/03/lg-display-becomes-wor...
      • snthpy 7mo ago
        Thanks. Great explanation.
      • joecool1029 7mo ago
        So it's a Sharp MIP scaled up? https://sharpdevices.com/memory-lcd/ https://sharpdevices.com/memory-lcd/
        • topspin 7mo ago
          Sharp MIP makes every pixel an SRAM bit: near-zero current and no refresh necessary. The full color moral equivalent of Sharp MIP would be 3 DACs per pixel. TFT (à la LG Oxide) is closer to DRAM, except the charge level isn't just high/low. So, no, there is a meaningful difference in the nature of the circuits.
  • deleted 7mo ago
    [deleted]
  • WhyNotHugo 7mo ago
    PSR (panel self-refresh) lets you send a single frame from software and tell the display to keep using that. You don’t need to render 60 times the same frame in software just to keep that visible on screen.
    • TeMPOraL 7mo ago
      How often is that used? Is there a way to check? With the amount of bullshit animations all OSes come with these days, enabled by default, and most applications being webapp with their own secondary layer of animations, and with the typical developer's near-zero familiarity with how floating point numbers behave, I imagine there's nearly always some animation somewhere, almost but not quite eased to a stop, that's making subtle color changes across some chunk of the screen - not enough to notice, enough to change some pixel values several times per second. I wonder what existing mitigations are at play to prevent redisplay churn? It probably wouldn't matter on Windows today, but will matter with those low-refresh-rate screens.
      • throwaway2037 7mo ago
        Normally, your posts are very coherent, but this one flies on the rails. (Half joking: Did someone hack your account!?) I don't understand your rant here: > With the amount of bullshit animations all OSes come with these days, enabled by default, and most applications being webapp with their own secondary layer of animations, and with the typical developer's near-zero familiarity with how floating point numbers behave I use KDE/GNU/Linux, and I don't see a lot of unnecessary animations. Even at work where I use Win11, it seems fine. "[M]ost applications being webapp": This is a pretty wild claim. Again, I don't think any apps that I use on Linux are webapps, and most at work (on Win11) are not.
        • fidotron 7mo ago
          Seriously? What is _this_ comment? TeMPOraL makes perfect sense.
          • 7mo ago
• hedora 7mo ago
  This is an OLED display, so I don't think the control electronics are actually any less active. (They would be for LCD, which is where most of these low-refresh-rate optimizations make sense.) The connection between the GPU and the display has been run length encoded (or better) since forever, since that reduces the amount of energy used to send the next frame to the display controller. Maybe by "1Hz" they mean they also only send diffs between frames? That'd be a bigger win than "1Hz" for most use cases. But, to answer your question, the light emission and computation of the frames (which can be skipped for idle screen regions, regardless of frame rate) should dwarf the transmission cost of sending the frame from the GPU to the panel. The more I think about this, the less sense it makes. (The next step in my analysis would involve computing the wattage requirements of the CPU, GPU and light emission, then comparing that to the KWh of the laptop battery + advertised battery life.
  • karlgkk 7mo ago
    > The more I think about this, the less sense it makes And yet, it’s the fundamental technology enabling always on phone and smartwatch displays The intent of this is to reduce the time that the CPU, GPU, and display controller is in an active state (as well as small reductions in power of components in between those stages).
    • DoctorOetker 7mo ago
      for small screen sizes and low information density displays, like a watch that updates every second this makes a lot of sense it would make a lot of sense in situations where the average light generating energy is substantially smaller: pretend you are a single pixel on a screen (laptop, TV) which emits photons in a large cone of steradians, of which a viewer's pupil makes up a tiny pencil ray; 99.99% of the light just misses an observer's pupils. in this case this technology seems to offer few benefits, since the energy consumed by the link (generating a clock and transmitting data over wires) is dwarfed by the energy consumed in generating all this light (which mostly misses human eye pupils)! Now consider smart glasses / HUD's; the display designer knows the approximate position of the viewer's eyes. The optical train can be designed so that a significantly larger fraction of generated photons arrive on the retina. Indeed XReal or NReal's line of smart glasses consume about 0.5 W! In such a scenario the links energy consumption becomes a sizable proportion of the energy consumption; hence having a low energy state that still presents content but updates less frequently makes sense. One would have expected smart glasses to already outcompete smartphones and laptops, just by prolonged battery life, or conversely, splitting the difference in energy saved, one could keep half of the energy saved (doubling battery life) while allocating the other half of the energy for more intensive calculations (GPU, CPU etc.).
• jdub 7mo ago
  Before OLED (and similar), most displays were lit with LEDs (behind or around the screen, through a diffuser, then through liquid crystals) which was indeed the dominant power draw... like 90% or so! But the article is about an OLED display, so the pixels themselves are emitting light.
  • perching_aix 7mo ago
    > But the article is about an OLED display The article is about an LCD display, actually.
  • duskdozer 7mo ago
    I just wish "we" wouldn't have discarded the option to use pure black for dark modes in favor of a seemingly ever-brightening blue-grey...
• Veedrac 7mo ago
  I think the idea is that in an always-on display mode, most of the screen is black and the rest is dim, so circuitry power budget becomes a much larger fraction of overhead.
  • 01HNNWZ0MV43FF 7mo ago
    Ohh like property tax on a vacant building
• alok-g 7mo ago
  I used to be a display architect about 15 years back (for Qualcomm mirasol, et al), so my knowledge of the specifics / numbers is outdated. Sharing what I know. High pixel density displays have disproportionately higher display refresh power (not just proportional to the total number of pixels as the column lines capacitances need to be driven again for writing each row of pixels). This was an important concern as high pixel densities were coming along. Display needs fast refreshing not just because pixel would lose charge, but because the a refresh can be visible or result in flicker. Some pixels tech require flipping polarity on each refresh but the curves are not exactly symmetric between polarities, and further, this can vary across the panel. A fast enough refresh hides the mismatch.
  • thisislife2 7mo ago
    Since you are knowledgable about this, do you have any idea what happened to Mirasol technology? I was fascinated by those colour e-paper like displays, and disappointed when plans to manufacture it was shelved. Then I learnt Apple purchased it but it looks more like a patent padding purchase than for tech development as nothing has come out of it form Apple too. Is it in some way still being developed or parts of its research tech being used in display development?
    • alok-g 7mo ago
      Being a key technology architect for it (not the core inventor), I know all about it, and then some more! I cannot however talk publicly about it. :-( It has been a disappointment for me as well. I had worked on it for nearly eight years. The idea was so interesting--using thin-film interference for creating images is akin to shaping Newton's rings into arbitrary images, something which even Newton would not have imagined! The demos and comparisons we had shown to various industry leaders and sometimes publicly were often instantly compelling. The people/engineers in the team were mostly the best I have ever worked with, and with whom I still maintain a great connection. But unfortunately, there were problems (not saying how much tech how much people) that were recognized by some but never got (timely) addressed. And a tech like it does not exist till date. I do not think anything on it is being developed further. The earliest of the patents would have expired by now. Liquavista, Pixtronics, etc., have been alternative display technologies that also ultimately didn't make the impact desired, AFAIK. Meanwhile, LCDs developed high pixel densities (which led to pressures on mirasol tech too), Plasma got sidelined. EInk displays have since then made good progress, though, in my opinion, are still far from colors and speeds that mirasol had. And of course, OLED, Quantum dots, ...
• dealfinder994 7mo ago
  [dead]
• perfmode 7mo ago
  [dead]
• mmcnl 7mo ago
  It doesn't. They take extreme use cases such as watching video until the battery depletes at maximum brightness where 90% of power consumption is the display. But in realistic use cases the fraction of power draw consumed by the display is much smaller when the CPU is actually doing things.
  • kjkjadksj 7mo ago
    For whatever reason I keep catching my macbook on max brightness. Maybe not an unrealistic test.
• elif 7mo ago
  Your GPU rendering 1 frame vs your GPU rendering 60 frames.
  • kinematikk 7mo ago
    In cases where 1hz mode is feasable the gpu doesn't render 60 fps anyways
• veqq 7mo ago
  Really disappointing to only learn this after a decade, but on Linux changing from 60hz to 40hz decreased my power draw by 40% in the last hour since reading this comment.