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LG's new 1Hz display is the secret behind a new laptop's battery life

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31–40 of 186 posts

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#31

Apple introduced variable refresh rate back in 2015. That’s over a decade ago, I’m sure there’s some new tech involved here, but quite the omission.

Stroke CRT displays been able to do variable refresh rate since like the 80s, quite the omission there buddy.

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#32
> 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?

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#33
post #2

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...

Phones and watches do that with LTPO OLED which I don't believe exists at higher screen sizes although I'm not sure why. This is supposed to be special because it isn't OLED so should be able to get brighter and not have to worry about burn in.

LTPO has problems with uniformity of brightness, that get worse the larger the panels are. On a phone screen, this is usually not perceivable, but if you made a 27" screen out of it, most such screens would be visibly brighter in some corner or other.

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#34
Anyone who has accidentally snapped the controller off a working LCD can tell you that the pixel capacitance keeps the colours approximately correct for about 10 seconds before it all becomes a murky shadowy mess...

So it makes sense you could cut the refresh time down to a second to save power...

Although one wonders if it's worth it when the backlight uses far more power than the control electronics...

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#35
post #15

So if a pixel is not refreshed, it doesn't use any power?

It does, especially with LCDs like this, where the backlight is the primary driver of the power consumption of the panel.

I'm not even sure how they got their 48% figure. Sounds like a whole-system measurement, maybe that's the trick.

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#36

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…

With current LCD controllers but new drivers/firmware you could selectively refresh horizontal stripes of the screen at different rates if you wanted to.

I don't think you could divide vertically though.

Don't think anyone has done this yet. You could be the first.

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#37
post #32

> 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?

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.

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#38

Anyone who has accidentally snapped the controller off a working LCD can tell you that the pixel capacitance keeps the colours approximately correct for about 10 seconds before it all becomes a murky shadowy mess... So it makes sense you could cut the refresh time down to a second to save power... Although one wonders if it's worth it when the backlight uses far more power than the control electronics...

It's for OLED screens, so there's no backlight, but also no persistence.

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#39
post #32

> 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?

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

Re: LG's new 1Hz display is the secret behind a new laptop's battery life

#40

Apple introduced variable refresh rate back in 2015. That’s over a decade ago, I’m sure there’s some new tech involved here, but quite the omission.

And if Apple introduced it a decade ago, then it's at least five years older than that.

What's new here is the 1 Hz minimum.

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