Attempting 180Hz at 4K 8bpc via HDMI 2.1 without DSC (MSI MPG 322URX)

[bjshnog]

At 4K and via HDMI 2.1 (3080 so no DP 2.1), this monitor normally allows 240Hz with DSC and 120Hz without. According to my* bandwidth calculations, it should be possible to achieve 180Hz 4K 8bpc without DSC on HDMI 2.1.

I've tried adding it in a detailed resolution slot (CVT-RB2), but the refresh rate goes red just before 75Hz. I googled a bunch, and the best I've been able to determine (I don't fully understand it though) is that it has something to do with pixel clock, and that higher refresh rates would need to go in a DisplayID extension block, so I added one of those and I'm able to define the detailed resolution in there.

However, upon restarting the driver, the new refresh rate doesn't appear anywhere (Windows advanced display settings, etc). Also, it seems like any change breaks NVIDIA Control Panel, removing almost all the settings categories, until I reset the monitor in CRU. Not sure if that is normal, but it happens with both of my monitors (it also happened before I got my second monitor).

I don't really know what to try next or if I should give up, so I'm posting here to see if I can get advice. Thanks.

[ToastyX]

RTX 3000/4000-series GPUs only support up to about 1350 MHz pixel clock without DSC. 5000-series GPUs might support higher. NVIDIA control panel issue is a bug in their driver.

[bjshnog]

Ah, that would put the limit around 144Hz then... hardly worth the trouble IMO. Oh well. Thanks anyway.

Edit: Well, I tried anyway, and 144Hz does appear in the Windows advanced display settings where 160 and 180 don't. Good to know that works, at least. Passes the frame skipping test (in Chrome).

[bubblyeducate]

(03-10-2025 06:27 AM)bjshnog Wrote:  At 4K and via HDMI 2.1 (3080 so no DP 2.1), this monitor normally allows 240Hz with DSC and 120Hz without. According to my* bandwidth calculations, it should be possible to achieve 180Hz 4K 8bpc without DSC on HDMI 2.1.

I've tried adding it in a detailed resolution slot (CVT- Geometry Dash RB2), but the refresh rate goes red just before 75Hz. I googled a bunch, and the best I've been able to determine (I don't fully understand it though) is that it has something to do with pixel clock, and that higher refresh rates would need to go in a DisplayID extension block, so I added one of those and I'm able to define the detailed resolution in there.

However, upon restarting the driver, the new refresh rate doesn't appear anywhere (Windows advanced display settings, etc). Also, it seems like any change breaks NVIDIA Control Panel, removing almost all the settings categories, until I reset the monitor in CRU. Not sure if that is normal, but it happens with both of my monitors (it also happened before I got my second monitor).

I don't really know what to try next or if I should give up, so I'm posting here to see if I can get advice. Thanks.

I think you might need to experiment with settings like subsampling (4:2:2), lower color depth, or even slightly lower refresh rate. If that doesn't work, maybe reconsider using DSC for 240Hz or just stick with the native 120Hz.