71–80 of 186 posts
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Copying , Draw() is called 60 times a second .
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.
Earlier quoted context omitted.
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.
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.
> 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 understand that the control electronics are 60x more active at 60 Hz than 1 Hz, but shouldn't the light emission itself be the dominant source of power consumption by far?
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.
The article is about an LCD display, actually.
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For sample-and-hold panel technologies like LCD and OLED, refresh is about updating the pixel state (color). There is a process that takes place for that even when the pixel data remains unchanged between frames. However, the pixels still need to emit light between refreshes, which for LCD is a backlight but for OLED are the pixel themselves. The light emission is often regulated using PWM at a higher frequency than…
OLED is fundamentally not sample and hold, because it is using PWM, right? Ignoring switching costs, keeping a sample-and-hold LED at 0%, 50% and 100% brightness all cost zero energy. For an OLED, the costs are closer to linear in the duty cycle (again, ignoring switching costs, but those are happening much faster than the framerate for OLED, right?) (Also, according to another comment, the panel manufacturer says th…
> 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 understand that the control electronics are 60x more active at 60 Hz than 1 Hz, but shouldn't the light emission itself be the dominant source of power consumption by far?
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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
Why? Surely copying the same pixels out sixty times doesn't take that much power?
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-wor...
Sorry, might be obvious to some, but is that rate applied to the whole screen or can certain parts be limited to 1Hz whilst others are at a higher rate? The ability to vary it seems like it would be valuable as there are significant portions of a screen that remain fairly static for longer periods but equally there are sections that would need to change more often and would thus mess with the ability to stick to a lo…
From what I understand, the laptop will reduce the refresh rate (of the entire display) to as low as 1Hz if what is being displayed effectively “allows” it. For example: - reading an article with intermittent scrolling - typing with periodic breaks
Haven't phones, watches and tablets been using low refresh rates to enable battery improvements for a while? The Apple Watch Series 5 (2019) has a refresh rate down to 1Hz. M4 iPad Pro lacks always-on display despite OLED panel with variable refresh rate (2024): https://9to5mac.com/2024/05/09/m4-ipad-pro-always-on-display...
OLED iPad dont have always on because of burn-in. Considering people certainly use it as photo frame, notification and time daahboars, kitchen recipe book, etc. Less of a problem for iphones that unlikely to stay for a week in the same place plugged in and unused.
Saving battery is nice, but I'm not leaving Linux for that misery any time soon
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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…
> 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).
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.).