DIY 240Hz Non-interpolated zero-buffer display.

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cirthix
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DIY 240Hz Non-interpolated zero-buffer display.

Post by cirthix » 20 Dec 2013, 16:20

Self-made interface board. DLDVI input to 4ch LVDS.

Tested with gtx 660ti, gtx 580, and hd7970. All worked perfectly after removing pixelclock limit in drivers.

Glitch-free at 240Hz (530MHz pixelclock). LED PWM frequency set to 16KHz. Lightboost and strobing is NOT supported. It has two edids, one only presenting 1080p@240Hz(forces all apps to run at 240Hz all the time, since no other modes are supported), the other offering 120Hz and 60Hz for compatibility's sake (eg: before drivers are patched).

phpBB [video]


Boards specifically with VG278HE internal connections will be available for sale in mid-january. email for details. cirthix at gmail.com

Other models with 120/144Hz panels may work but might require cabling modifications. I will help you do this if needed.

Side-note: the board can also handle 2560*1600@120Hz, but there were significant panel artifacts (lines and underdriven areas) when testing with lm300wq5-sla1.

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Chief Blur Buster
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Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by Chief Blur Buster » 20 Dec 2013, 16:40

Hey,
I have been in touch with you, and I'm glad you are here now!

VERY impressive electronics engineering there -- beating the monitor manufacturers to a true 240Hz LCD capability, direct-driven from a computer. At 1/240sec real-time scanout with no buffering. Even if you use VSYNC ON, you're getting input lag if as little as 4ms maximum with VSYNC ON. That would be the world's lowest VSYNC ON input lag -- for people who hate tearing. And in fact, this would be perfect for future G-SYNC too -- raising the 144fps cap to 240fps.

Thanks for posting here. Your project is "Area 51" league here -- and belongs here, too! I've already blogged about your project at:
http://www.blurbusters.com/true-240hz-l ... s-project/

It's good to see you in these forums. You've done some incredible engineering there.
Feel free to use this thread to followup on this project, especially if you're making new modifications to this!

I would also like display manufacturers to work on true-240Hz LCD's (with good color quality), preferably combined with G-SYNC. Having G-SYNC with a higher framerate cap would be great for uber-competitive players that want to play at faster than 144fps!
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Ahigh
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Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by Ahigh » 24 Dec 2013, 03:38

Nice work!

Q83Ia7ta
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Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by Q83Ia7ta » 31 Dec 2013, 22:55

By the way: input of 144hz is bandwidth limit of DL-DVI or lcd panels?

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Ahigh
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Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by Ahigh » 01 Jan 2014, 01:21

Sign me up as your first customer. I have a VG278HE here ready and waiting!!!

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shadman
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Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by shadman » 01 Jan 2014, 06:19

Q83Ia7ta wrote:By the way: input of 144hz is bandwidth limit of DL-DVI or lcd panels?
Assuming you mean 1080p, then it is not a DVI limitation but part of the monitor. I'm not 100% sure which part though.

Haste
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Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by Haste » 01 Jan 2014, 21:59

Very nice work cirthix!
Congrats on making the first true 240Hz LCD happen.
Monitor: Asus ROG Swift PG279Q

Q83Ia7ta
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Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by Q83Ia7ta » 01 Jan 2014, 23:26

shadman wrote:
Q83Ia7ta wrote:By the way: input of 144hz is bandwidth limit of DL-DVI or lcd panels?
Assuming you mean 1080p, then it is not a DVI limitation but part of the monitor. I'm not 100% sure which part though.
Yeah i was thinking about 1920x1080@144hz. If you sure it's not limit of DL-DVI standard then it's some part main board. I don't get why all new gaming monitors from benq, asus, iiyama, viewsonic, aoc, phillips, etc are using this 144hz limit. Even first and new cheap chinese monitor HKC X1 uses 144hz.

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Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by Chief Blur Buster » 02 Jan 2014, 10:06

Q83Ia7ta wrote:
shadman wrote:
Q83Ia7ta wrote:By the way: input of 144hz is bandwidth limit of DL-DVI or lcd panels?
Assuming you mean 1080p, then it is not a DVI limitation but part of the monitor.
DL-DVI is overclockable to dotclocks necessary for 2560x1440p 120Hz, which is roughly equivalent in dotclock to 1920x1080 240Hz. So, 1080p 240hz isn't part of DL-DVI spec, but it's overclockable to get there.

Also, two DisplayPort channels also has enough bandwidth to output 1080p 240Hz.

Also, refreshing this panel 240 cycles per second, will have some color degradation, so keep this in mind. Input lag will be ultra-low on this panel, since this is a zero buffered LCD, with only a ~4ms difference between top edge of screen and bottom edge of screen. (unlike ~8ms difference between top/bottom for 120Hz scanout, and ~16ms difference between top/bottom for 60Hz scanout).

I am really looking forward to seeing what non-strobed 240Hz looks like. Being an estimated 1/240sec = 4.1ms sample-and-hold, I expect it's roughly somewhere between 144Hz non-strobed (6.9ms) and LightBoost=100% (2.4ms) in motion clarity.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

Akoni
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Joined: 03 Jan 2014, 17:28

Re: DIY 240Hz Non-interpolated zero-buffer display.

Post by Akoni » 03 Jan 2014, 18:15

wow!

you my friend, are awesome

engineering skills to the max. do you have any other information on the upgrade?

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