Overdrive: The Secret to Achieving Faster Frame Rates

When it comes to dealing with overdrive, it's a fun one to figure out. Overdrive essentially works like this: you've got a pixel and you want to take it from level 100 to level 200. This might take around 8 milliseconds natively. However, if that's not good enough for the performance you want, we can tell that pixel I want to reach 250. And because that's a bigger change, it's going to reach our actual desired level of 200 faster. So, you're basically giving it a bigger kick, which might get there in just four or six milliseconds. The trick though is to not go too high or you'll get too high of a value, overshooting the intended target.

At 60 Hertz Fixed Refresh Rate, this is relatively simple. The monitor just has a lookup table built into it of what it should shoot for in order to have the value be correct by the next 16.6 millisecond refresh cycle. With variable refresh rate, however, it has to compensate how much of an extra kick it's giving according to how much more or how much less time it's going to have to get to the actual desired value. Even driving the LEDs in the backlight is a complicated matter.

The G-Sync Module: The Heart of Variable Refresh Rate Technology

At its heart is the powerful G-Sync processor that contains most of G-Sync's special sauce. Around it is kind of like the motherboard of a monitor - something that the manufacturer of the monitor would customize depending on what they want for display connectors, USB hubs, built-in audio, and so on. Finally, there are the driver ICS (Integrated Circuit Systems) right here, which take a digital signal from the G-Sync module scaler to determine and write the correct luminance level for each of the 384 LEDs that make up the backlight. They output a given DC voltage to each of the 16 transistors that drive the current that actually lights up the individual LED in each zone just the right amount.

The Challenge of High Refresh Rates

A Corsair Commander Pro can drive dozens of RGB LEDs per channel with like four wires, but at 144 Hertz, you've got under seven milliseconds per frame. You have to both determine and write all 384 of those values each frame and add up to a thousand nitspeak brightness, so this is not a trivial task.

The Meeting that Built the Most Difficult TV

"I can imagine the meeting where they decided to build this thing right now like all right team, we've never built a TV before, so the plan is to build the most difficult one. Good luck everyone and break." This leads us finally to certification - the third and final stage of variable refresh rate technology. The point at which NVIDIA receives the first finished units of each display and goes through that whole ordeal again to ensure that nothing got lost in translation.

Behind the Scenes: A Deeper Appreciation for G-Sync Technology

Going behind the scenes today gave me a much deeper appreciation for what NVIDIA has been doing in the display industry. The eagle-eyed among you might have noticed that one of those backlight driver boards on this prototype has an NVIDIA silkscreen on it, while the other one has something else that's because as part of developing G-Sync Ultimate, NVIDIA actually created the reference design for these driver boards since nobody had ever done a 384-zone 27-inch panel before.

The Future of G-Sync: Three Tiers of Certification

Now there are three tiers of G-Sync - G-Sync compatible displays don't go through anything that you saw today, NVIDIA performs four variable refresh rate tests to ensure that they're suitable for a basic VRR gaming experience. Then there's G-Sync and G-Sync Ultimate, where you're getting the deep collaboration between your graphics card manufacturer and your display maker, with ultimate also including support for HDR gaming.

Conclusion

That's it for today, guys! Massive thank you to you for watching and to NVIDIA for sponsoring this video and just straight up allowing us a peek behind the kimono. This was absolutely incredible. If this video sucked, you know what to do - but if it was awesome, get subscribed, hit the like button or check out the link to where to buy the stuff we featured in the video description. Also down there is our merch store which has cool shirts like this one and our community forum which you should totally join, especially if you have any questions about building a fantastic gaming rig or buying a variable refresh rate monitor or whatever the case may be.

"WEBVTTKind: captionsLanguage: ennvidia's original g-sync technology has largely kept the promises that it made five years ago of eliminating tearing input lag and stutter in high-end gaming displays but the how of this technology is something that they've kept under wraps until now which is what makes today's video really really special because nvidia sponsored our trip down to santa clara today where we will be the first non-nvidia personnel to ever see one of their g-sync optical labs so let's go find out how you make a gaming monitor shall we now nvidia doesn't actually manufacture display panels that work is best left to the experts at samsung lg display au optronics and the like but inside this cage come on get around here behind me is a sample of every g-sync monitor that has ever been built and the thing is there's far more to creating a great finished gaming display than just taking whatever panel those guys hand you slapping it into an enclosure and calling it a day in fact while the situation has improved a lot especially on the desktop nvidia still fails over 50 percent of the laptop displays that get sent to them for validation so each one of these assuming that they don't immediately fail the more basic checks will get subjected to over 300 tests some of which take hours or even multiple days to run so i feel kind of bad for the techs who drew the short straw for our visit today and had to shut down you see the issue and actually the reason that the walls are all painted black in here is that with our filming lights on they can't run any real tests because the results will be invalid so we're gonna try to get out of their way real quick here on this bench then is our first real test here so it's a pretty simple one on the surface but it's one that will weed out a surprising number of variable refresh rate displays so our gpu here runs a benchmark with extreme swings in the frame rate which is designed to expose weaknesses in the t-con or timing controller which is the part of the panel that takes the output from the scalar and translates it into something that the actual drivers of the tft matrix can understand now the results of these failures are usually quite obvious because if a t-con experiences a firmware problem for example causing an overflow condition its go-to emergency response is generally to blank out parts of the panel or even the entire thing temporarily to prevent it from being damaged apparently they actually had one of those come through here just the other day but that doesn't mean that running these tests is simple for one thing these kinds of problems can be weird edge cases i mean that's why the manufacturer didn't notice them so they can take a long time to manifest which is why they run for up to 48 hours before assigning a pass and for another just hooking a source up to a bare notebook lcd is an ordeal and a half so of course you need a mobile gpu in order to validate mobile displays but using a standard desktop test bench would save you a lot of time so check out this frankenstein creation i've actually got another one right here so this according to the folks here is a touring mobile gpu but soldered onto a development board with just like this cooler just plugs straight into 12 volt power it just runs at full speed all the time that's why these things are so loud and then it's just bristling with diagnostic readouts and and uh sort of measurement points and then there's then there's the really cool stuff so this right here is our dvi output or something that's on a daughter board for some reason and on the back here this is really cool so these interfaces back here are designed for all of the different implementations of embedded displayport that you might see from the various panel manufacturers so they make their own daughterboard pcbs here so they can adapt this weird development card to run any display that they want on to our next test though one of the hardest parts of creating a variable refresh rate display is preventing flickering but the thing is not everyone perceives flicker the same and even if a flicker isn't visible to the eye it can still cause fatigue and headaches so that is where this test comes in now it doesn't look like much but the lab techs here can change this boring gray screen to output any refresh rate they want then they use this klein instrument's k10a a basic luminance meter to measure the amplitude and decibels of any changes in the output brightness then that is of course assuming that the panel makes it this far they use this special box of nvidia's own creation to kind of like a like a doctor checking your like heartbeat or something check all the different areas of the panel to see which one is the worst and then ensure that even that is still within spec rounding out panel selection is a whole battery of other tests color reproduction color gamut absolute luminance native contrast ratio pixel response times you pretty much name it then we can move into this room once a panel is validated it can move on to stage two actual display development at this point things get a lot pickier so this forty to fifty thousand dollar xy positioning jib is precise to one tenth of a millimeter so what they do is they light up the display so the one that we're looking at right here is a g-sync ultimate unit with hdr 10 support at up to 1 000 nits peak brightness and then they take measurements across the entire surface to ensure that it's uniform it's pretty freaking intense except that is just scratching the surface so this display also features 384 zone full array backlighting and handling that evenly is really freaking tricky in this test nvidia is evaluating each of the individual leds that makes up the backlight array not just off and at full force but at its various steps in between because you guys gotta understand they need to account not just for the drive level of each one of these zones but even the neighboring light lead from other zones around them and then making matters worse the whole thing has got to work perfectly at every brightness level and every refresh rate so then once the luminance behavior of the panel is characterized it's either fantastic out of the box ready to go or much more likely it needs some work it's no bloody wonder that these 4k 144hz hdr displays got delayed right speaking of delays in this room also uh professionally darkened out don't you love it when like an engineer is given a problem and told to solve it quickly i love this um anyway in here is one of nvidia's bfgd or big format gaming displays now the process you're seeing here is nothing special if you've ever professionally calibrated a display before basically a signal generator so this laptop outputs a known value let's say white or other more different white or red or something and then a sensor like this spectroradiometer checks how close it is to what it's expecting but what's different about nvidia's approach here is that instead of just calibrating finished displays during the development process they're jumping in to make sure that there are no underlying issues with the technology that are going to crop up while operating in variable refresh rate mode that can't be corrected because the thing is many lcd characteristics change when the refresh rate changes another fun one to deal with is overdrive so overdrive basically works like this you've got a pixel and you want to take it from level 100 to level 200 which might take it let's say 8 milliseconds natively well if that's not good enough for the performance you want with overdrive we can tell that pixel i want 250. and because that's a bigger change it's going to reach our actual desired level of 200 faster so you're basically giving it a bigger kick so you might get there in just four or six milliseconds the trick though is to not go too high or you'll get too high of a value overshooting the intended target now here's the thing at 60 hertz fixed refresh rate this is relatively simple so the monitor just has a lookup table built into it of what it should shoot for in order to have the value be correct by the next 16.6 millisecond refresh cycle with variable refresh rate well it has to compensate how much of an extra kick it's giving according to how much more or how much less time it's going to have to get to the actual desired value and even driving the leds in the backlight is a complicated matter so this is the back of a g-sync ultimate desktop monitor but the internal guts here are actually fundamentally similar to the bfgd that we just saw so at its heart is the powerful g-sync processor that contains much of g-sync's special sauce then around it is kind of like the uh the motherboard of a monitor so this here is something that the manufacturer of the monitor would customize depending on what they want for display connectors usb hubs built-in audio that sort of thing then finally there's a third part here so these are kind of like the wings that make g-sync hdr fly so these driver ics right here take a digital signal from the g-sync module scaler for what the luminance level should be for each of the 384 leds that make up the backlight here then they output a given dc voltage to each of the 16 transistors that drive the current that actually lights up the individual led in each zone just the right amount but like hold on hold on a second here a corsair commander pro can drive dozens of rgb leds per channel with like four wires what is all of this for well here's the thing at 144 hertz you've got under seven milliseconds per frame and you have to both determine and write all 384 of those values each frame and add up to a thousand nitspeak brightness so this is not a trivial task like man i can imagine the meeting where they decided to build this thing right now like all right team so we've never built a tv before so the plan is to build the most difficult one lol good luck everyone and break which leads us finally to certification now the third and final stage might not be that visually interesting but it's arguably the most important so this is the point at which nvidia receives the first finished units of each display and goes through that whole ordeal again to ensure that nothing got lost in translation and i have to say going behind the scenes today gave me a much deeper appreciation for what nvidia has been doing in the display industry the eagle-eyed among you for example might have noticed that one of those backlight driver boards on this prototype has an nvidia silkscreen on it while the other one has something else that's because as part of developing g-sync ultimate nvidia actually created the reference design for these driver boards since nobody had ever done a 384-zone 27-inch panel before now unfortunately i wasn't able to show you guys everything that i saw but what i can say is that my experience today has shown me definitively that this is far more than just a a rubber stamping certification fee operation so then there are three tiers of g-sync now g-sync compatible displays don't go through anything that you saw today nvidia performs four variable refresh rate tests to ensure that they're suitable for a basic vrr gaming experience then there's g-sync and g-sync ultimate where you're getting the deep collaboration between your graphics card manufacturer and your display maker with ultimate also including support for hdr gaming which as we've discussed in the past looks pretty freaking sick so that's it for today guys massive thank you to you for watching and to nvidia for sponsoring this video and just straight up allowing us a peek behind the kimono this was absolutely incredible if this video sucked you guys know what to do but if it was awesome get subscribed hit the like button or check out the link to where to buy the stuff we featured in the video description also down there is our merch store which has cool shirts like this one and our community forum which you should totally join especially if you have any questions about building a fantastic gaming rig or buying a variable refresh rate monitor or whatever the case may benvidia's original g-sync technology has largely kept the promises that it made five years ago of eliminating tearing input lag and stutter in high-end gaming displays but the how of this technology is something that they've kept under wraps until now which is what makes today's video really really special because nvidia sponsored our trip down to santa clara today where we will be the first non-nvidia personnel to ever see one of their g-sync optical labs so let's go find out how you make a gaming monitor shall we now nvidia doesn't actually manufacture display panels that work is best left to the experts at samsung lg display au optronics and the like but inside this cage come on get around here behind me is a sample of every g-sync monitor that has ever been built and the thing is there's far more to creating a great finished gaming display than just taking whatever panel those guys hand you slapping it into an enclosure and calling it a day in fact while the situation has improved a lot especially on the desktop nvidia still fails over 50 percent of the laptop displays that get sent to them for validation so each one of these assuming that they don't immediately fail the more basic checks will get subjected to over 300 tests some of which take hours or even multiple days to run so i feel kind of bad for the techs who drew the short straw for our visit today and had to shut down you see the issue and actually the reason that the walls are all painted black in here is that with our filming lights on they can't run any real tests because the results will be invalid so we're gonna try to get out of their way real quick here on this bench then is our first real test here so it's a pretty simple one on the surface but it's one that will weed out a surprising number of variable refresh rate displays so our gpu here runs a benchmark with extreme swings in the frame rate which is designed to expose weaknesses in the t-con or timing controller which is the part of the panel that takes the output from the scalar and translates it into something that the actual drivers of the tft matrix can understand now the results of these failures are usually quite obvious because if a t-con experiences a firmware problem for example causing an overflow condition its go-to emergency response is generally to blank out parts of the panel or even the entire thing temporarily to prevent it from being damaged apparently they actually had one of those come through here just the other day but that doesn't mean that running these tests is simple for one thing these kinds of problems can be weird edge cases i mean that's why the manufacturer didn't notice them so they can take a long time to manifest which is why they run for up to 48 hours before assigning a pass and for another just hooking a source up to a bare notebook lcd is an ordeal and a half so of course you need a mobile gpu in order to validate mobile displays but using a standard desktop test bench would save you a lot of time so check out this frankenstein creation i've actually got another one right here so this according to the folks here is a touring mobile gpu but soldered onto a development board with just like this cooler just plugs straight into 12 volt power it just runs at full speed all the time that's why these things are so loud and then it's just bristling with diagnostic readouts and and uh sort of measurement points and then there's then there's the really cool stuff so this right here is our dvi output or something that's on a daughter board for some reason and on the back here this is really cool so these interfaces back here are designed for all of the different implementations of embedded displayport that you might see from the various panel manufacturers so they make their own daughterboard pcbs here so they can adapt this weird development card to run any display that they want on to our next test though one of the hardest parts of creating a variable refresh rate display is preventing flickering but the thing is not everyone perceives flicker the same and even if a flicker isn't visible to the eye it can still cause fatigue and headaches so that is where this test comes in now it doesn't look like much but the lab techs here can change this boring gray screen to output any refresh rate they want then they use this klein instrument's k10a a basic luminance meter to measure the amplitude and decibels of any changes in the output brightness then that is of course assuming that the panel makes it this far they use this special box of nvidia's own creation to kind of like a like a doctor checking your like heartbeat or something check all the different areas of the panel to see which one is the worst and then ensure that even that is still within spec rounding out panel selection is a whole battery of other tests color reproduction color gamut absolute luminance native contrast ratio pixel response times you pretty much name it then we can move into this room once a panel is validated it can move on to stage two actual display development at this point things get a lot pickier so this forty to fifty thousand dollar xy positioning jib is precise to one tenth of a millimeter so what they do is they light up the display so the one that we're looking at right here is a g-sync ultimate unit with hdr 10 support at up to 1 000 nits peak brightness and then they take measurements across the entire surface to ensure that it's uniform it's pretty freaking intense except that is just scratching the surface so this display also features 384 zone full array backlighting and handling that evenly is really freaking tricky in this test nvidia is evaluating each of the individual leds that makes up the backlight array not just off and at full force but at its various steps in between because you guys gotta understand they need to account not just for the drive level of each one of these zones but even the neighboring light lead from other zones around them and then making matters worse the whole thing has got to work perfectly at every brightness level and every refresh rate so then once the luminance behavior of the panel is characterized it's either fantastic out of the box ready to go or much more likely it needs some work it's no bloody wonder that these 4k 144hz hdr displays got delayed right speaking of delays in this room also uh professionally darkened out don't you love it when like an engineer is given a problem and told to solve it quickly i love this um anyway in here is one of nvidia's bfgd or big format gaming displays now the process you're seeing here is nothing special if you've ever professionally calibrated a display before basically a signal generator so this laptop outputs a known value let's say white or other more different white or red or something and then a sensor like this spectroradiometer checks how close it is to what it's expecting but what's different about nvidia's approach here is that instead of just calibrating finished displays during the development process they're jumping in to make sure that there are no underlying issues with the technology that are going to crop up while operating in variable refresh rate mode that can't be corrected because the thing is many lcd characteristics change when the refresh rate changes another fun one to deal with is overdrive so overdrive basically works like this you've got a pixel and you want to take it from level 100 to level 200 which might take it let's say 8 milliseconds natively well if that's not good enough for the performance you want with overdrive we can tell that pixel i want 250. and because that's a bigger change it's going to reach our actual desired level of 200 faster so you're basically giving it a bigger kick so you might get there in just four or six milliseconds the trick though is to not go too high or you'll get too high of a value overshooting the intended target now here's the thing at 60 hertz fixed refresh rate this is relatively simple so the monitor just has a lookup table built into it of what it should shoot for in order to have the value be correct by the next 16.6 millisecond refresh cycle with variable refresh rate well it has to compensate how much of an extra kick it's giving according to how much more or how much less time it's going to have to get to the actual desired value and even driving the leds in the backlight is a complicated matter so this is the back of a g-sync ultimate desktop monitor but the internal guts here are actually fundamentally similar to the bfgd that we just saw so at its heart is the powerful g-sync processor that contains much of g-sync's special sauce then around it is kind of like the uh the motherboard of a monitor so this here is something that the manufacturer of the monitor would customize depending on what they want for display connectors usb hubs built-in audio that sort of thing then finally there's a third part here so these are kind of like the wings that make g-sync hdr fly so these driver ics right here take a digital signal from the g-sync module scaler for what the luminance level should be for each of the 384 leds that make up the backlight here then they output a given dc voltage to each of the 16 transistors that drive the current that actually lights up the individual led in each zone just the right amount but like hold on hold on a second here a corsair commander pro can drive dozens of rgb leds per channel with like four wires what is all of this for well here's the thing at 144 hertz you've got under seven milliseconds per frame and you have to both determine and write all 384 of those values each frame and add up to a thousand nitspeak brightness so this is not a trivial task like man i can imagine the meeting where they decided to build this thing right now like all right team so we've never built a tv before so the plan is to build the most difficult one lol good luck everyone and break which leads us finally to certification now the third and final stage might not be that visually interesting but it's arguably the most important so this is the point at which nvidia receives the first finished units of each display and goes through that whole ordeal again to ensure that nothing got lost in translation and i have to say going behind the scenes today gave me a much deeper appreciation for what nvidia has been doing in the display industry the eagle-eyed among you for example might have noticed that one of those backlight driver boards on this prototype has an nvidia silkscreen on it while the other one has something else that's because as part of developing g-sync ultimate nvidia actually created the reference design for these driver boards since nobody had ever done a 384-zone 27-inch panel before now unfortunately i wasn't able to show you guys everything that i saw but what i can say is that my experience today has shown me definitively that this is far more than just a a rubber stamping certification fee operation so then there are three tiers of g-sync now g-sync compatible displays don't go through anything that you saw today nvidia performs four variable refresh rate tests to ensure that they're suitable for a basic vrr gaming experience then there's g-sync and g-sync ultimate where you're getting the deep collaboration between your graphics card manufacturer and your display maker with ultimate also including support for hdr gaming which as we've discussed in the past looks pretty freaking sick so that's it for today guys massive thank you to you for watching and to nvidia for sponsoring this video and just straight up allowing us a peek behind the kimono this was absolutely incredible if this video sucked you guys know what to do but if it was awesome get subscribed hit the like button or check out the link to where to buy the stuff we featured in the video description also down there is our merch store which has cool shirts like this one and our community forum which you should totally join especially if you have any questions about building a fantastic gaming rig or buying a variable refresh rate monitor or whatever the case may be\n"