Triple 27" Odyssey OLED G6 monitors - DSC issue

[twilford]

I've encountered an issue trying to run triple Odyssey G6 OLED (G60SD) monitors. I'm only able to run 2 of the 3 monitors at a time. Nvidia detects the 3rd monitor, but won't allow me to set it as active.

From what I've read, 1440p can run up to 240hz over DisplayPort 1.4 and in order to use a higher refresh rate at that resolution DSC is needed for the increased amount of bandwidth it requires. According to Nvidia, GPUs have 4 internal heads and when a display is set to DSC mode, the GPU use 2 internal heads to drive the display. I think this is why Windows is only letting me use 2 of the 3 monitors at a time, the monitors are using DSC and taking up 2 of the internal heads each, leaving nothing left to run the 3rd. I think this is also why I'm able to run triple monitors using the regular Odyssey G6 monitors, but not my new Odyssey G6 OLEDs. I technically can run 3 at the same time if I go into the monitor settings for 2 of them and set the DisplayPort version from 1.4 to 1.1, but unfortunately the DisplayPort 1.1 interface doesn't allow gsync, HDR, or refresh rates higher than 60hz for 1440p.

I was hoping for a solution or possibly a firmware update for these G60SD monitors to allow toggling DSC or limiting the max refresh rate within the monitor settings so DSC isn't enabled. I was hoping to use all 3 at the same time over DisplayPort 1.4 and utilize HDR, gsync, and set the refresh rate to something higher than 60hz like 120hz or 240hz. Then I would be able to use these G6 monitors the exact same way I can do with the non-OLED versions.

https://nvidia.custhelp.com/app/answers/detail/a_id/5338/

[ddaniel51]

Which GPU&CPU are you using?

[twilford]

I have a Ryzen 7 5800X and a RTX 3080.

[ddaniel51]

I suggest you do an Internet search for "triple G6 monitors" to see others trials, tribulations, and solutions.

There is a hardware solution out there.

[twilford]

DisplayPort 1.4 has the bandwidth to run 1440p at 240hz without needing compression. That means my GPU has the ability to run all 3 monitors at 1440p with HDR on, gsync enabled, and 1 running at the full 360hz refresh rate while the other 2 run at 240hz. Running all of my monitors at max spec except having 2 of my 3 monitors, which are also the ones I'm not even gaming on, at 240hz instead of 360hz is a far cry from "crippling". I have one of the best GPUs available, but even the best card currently out wouldn't be able to run triple G60SD monitors because no card has 6 internal heads. The shortcoming is the monitor forcing DSC to be enabled at all times when it's not required for refresh rates at 240hz and under.

I've already searched for a solution and have found nothing, which makes sense given the problem that I explained in my original post. I'm guessing your suggestion for searching "triple G6 monitors" you didn't do yourself because the only results for that are people running the older non-OLED G6 monitors that only go up to 240hz, which is why that can be done. There is nothing for running triple G60SD monitors.

[ddaniel51]

Oh, I did do the searches before my Initial reply.  Did you check out the 7900 xt/xtx?

Anyway, good luck.

[TanMai24]

Did you try DisplayPort 1.2 for them? 

It is enabled by default if 10-bit colour and/or refresh rates exceeding 240 Hz are used, and is available on all DP versions AFTER 1.2. Since this monitor only supports v1.1 and v1.4, you have to "cheat" a DSC disable by setting the colour depth to 8-bit and any refresh rate not exceeding 240 Hz.

[twilford]

The G60SD only has DisplayPort version options for 1.4 and 1.1 in the OSD, no 1.2. Also, I've already tried using default color settings and Nvidia overrides for 8-bit color depth and have had no luck.

I've also read that Nvidia's DLDSR isn't available if DSC is being used and the options in Nvidia's control panel for them won't be available. This matches my testing because DLDSR is only available if I'm running DisplayPort 1.1 where DSC isn't being used or on my old monitors that aren't using DSC. Even if I just plug in one monitor, set the DisplayPort version to 1.4, set the color depth to 8-bit, turn off HDR, turn off gsync, and set the refresh rate to 60hz Nvidia's DLDSR isn't available so appears the monitor forces DSC on DisplayPort 1.4 regardless of any combination of settings.

[TanMai24]

Maybe we wait for oled G6 firmware update.