How to overclock G-Sync (Bonus: Unlocked Glitch State)

Talk about overclocking displays at a higher refresh rate. This includes homebrew, 165Hz, QNIX, Catleap, Overlord Tempest, SEIKI displays, certain HDTVs, and other overclockable displays.
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lexlazootin
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Re: How to overclock G-Sync (Bonus: Unlocked Glitch State)

Post by lexlazootin » 06 Sep 2017, 08:01

kalston wrote:Huum, wondering if this could me help create a custom 90hz refresh on my Rog Swift? I'll have to try when I get home.

This is purely to achieve perfect sync with my Oculus Rift when using Virtual Desktop. I've had no luck so far and I'm a sucker for perfect smoothness (g-sync user since day one) so when VD is capturing my monitor running at 144/120/100/85/60hz and turning it into 90hz it bothers me.
yea, so that's easy.

start with 100hz or 85hz and create a custom resolution.

You will see a pixel clock which is a specific value, you need to keep it within a range of that value, so if it's at 356.545 for example you might need to keep it between 350 and 360 for example.

adjust the Horizontal total either higher or lower to raise and lower the pixel clock, that should give you more room to adjust the HZ and stand within that value.

If it doesn't work at all with Horizontal Total, try changing with Vertical Total. One of these should be locked and not work when you change it. For my Benq 144hz G-Sync the VT was locked, for my Acer 240hz G-Sync my HT was locked.

That should be all you need to know to make it work at 90hz. ;)

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RealNC
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Re: How to overclock G-Sync (Bonus: Unlocked Glitch State)

Post by RealNC » 06 Sep 2017, 09:19

You don't need to create new refresh rates with g-sync monitors (unless you disable g-sync.) Just use the max refresh rate, cap to 90FPS, and voilà... there's your 90Hz.
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kalston
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Re: How to overclock G-Sync (Bonus: Unlocked Glitch State)

Post by kalston » 06 Sep 2017, 11:58

lexlazootin wrote:
kalston wrote:Huum, wondering if this could me help create a custom 90hz refresh on my Rog Swift? I'll have to try when I get home.

This is purely to achieve perfect sync with my Oculus Rift when using Virtual Desktop. I've had no luck so far and I'm a sucker for perfect smoothness (g-sync user since day one) so when VD is capturing my monitor running at 144/120/100/85/60hz and turning it into 90hz it bothers me.
yea, so that's easy.

start with 100hz or 85hz and create a custom resolution.

You will see a pixel clock which is a specific value, you need to keep it within a range of that value, so if it's at 356.545 for example you might need to keep it between 350 and 360 for example.

adjust the Horizontal total either higher or lower to raise and lower the pixel clock, that should give you more room to adjust the HZ and stand within that value.

If it doesn't work at all with Horizontal Total, try changing with Vertical Total. One of these should be locked and not work when you change it. For my Benq 144hz G-Sync the VT was locked, for my Acer 240hz G-Sync my HT was locked.

That should be all you need to know to make it work at 90hz. ;)
You're completely right, all I had to do was adjust the horizontal total, got it to work on the first try. Awesome, thanks :) Monitor reports 100hz but applications say 90hz and I'm not seeing any frame skipping whatsoever.

And @ RealNC when a VR application starts, nvidia disables g-sync automatically (and v-sync too). That also wouldn't work for video playback which is my main goal here

edit : OK so I did a bit more in depth testing: it doesn't actually work properly on the monitor itself, there is a consistent tear line near the top of the screen, regardless of v-sync or g-sync settings and regardless of the framerate too. (I used Quake 3 with different fps caps)

However, it works perfectly with Virtual Desktop in the Oculus Rift, there is no tearing at all and videos look as smooth as is to be expected with 90hz (not a multiple of 24fps so obviously not that great but way better than when I'm running the screen at any other hz). I also tried Quake 3 with a 91 fps cap and was getting a consistent stutter every second which makes sense right?

So I have achieved my goal but I can't say that the Rog Swift actually supports a 90hz custom resolution. I succeeded by starting from 100hz btw, with 85 it always gave me out of range (even had to reboot once as it stayed black :( ). I only adjusted horizontal total, it didn't want me to mess around with vertical.

edit 2 : now I see you mentioned that tearline issue already, guess I could mess around with values to try and fix it

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lexlazootin
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Re: How to overclock G-Sync (Bonus: Unlocked Glitch State)

Post by lexlazootin » 07 Sep 2017, 08:25

A constant tear-line might be fixed if you start with 100hz timing and go down or start with 85hz timings and go up since you didn't really say what you used.
kalston wrote:it didn't want me to mess around with vertical.
It should be locked and can't be changed, it will just go black. If you're testing a resolution and it goes black just hit enter and it will reset.

I've tried so many ridiculous settings with my 144hz G-Sync monitor and 240hz monitor, i doubt you will have any issue. The worst you'll have to do is use another display port to put into to reset what you've done.

kalston
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Re: How to overclock G-Sync (Bonus: Unlocked Glitch State)

Post by kalston » 07 Sep 2017, 12:00

Yea sorry if it wasn't clear, I started with 100hz, noted the pixel clock (410 something) then put in 90hz and raised the horizontal total until pixel clock was 407. That worked, but with a tear line.

When I tried starting from 85hz, I couldn't get anything other than a black screen (again, simply adjusting the horizontal to try and stay close to the 85hz pixel clock).

Now I also had a weird issue later that day, where the screen was stuck in this custom 90hz mode I got to work earlier. And I do mean stuck, changing the refresh rate or resolution (in windows or nvidia) did nothing, deleting the custom res did nothing either, and the screen said 100 while apps said 90 (v-sync also gave 90). I even rebooted and it was still stuck in that mode. Very odd.

So I just updated my nvidia drivers using the clean install option and that fixed it of course. I'm sure there are easier ways to fix it but I hadn't updated them for a couple of months so it seemed like a good time. I will look into this again later.

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