I have a problem. I got 3 screens which always seem to use DSC even when I change resolution/refresh rate to a natively supported format (e.g. 4K 60Hz). My Nvidia GPU refuses to work with more than 2 DSC screens at the same time. For the secondary/tertiary screen I’m fine with 4K@60Hz or 4K@120Hz, but as the screen does not allow me to turn off DSC I thought maybe there is a repeater that simply does not support DSC.
Anybody can recommend something like that? In the worst case I’ve to use a DP1.2 repeater but that would limit me to 4K30Hz which is meeh.
I have some questions. How do you know DSC is enabled? Also, why don’t you want DSC? DSC shouldn’t be enabled at 60HZ, but even if it is, all it does is help?
I know DSC is enabled because I can see all 3 screens in Windows and in the Nvidia control panel, but I can only enable 2 of them at the same time. This is a Nvidia limitation (it uses 2 heads per DSC monitor which limits the total amount of DSC screens to 2).
I’m not sure why DSC is active even at these low refresh rates.
The GPU is a 3080Ti and the screens are all Cooler Master Tempest GP27-FUS.
You might try getting a different cable? If it’s shoddy, maybe it’s causing DSC at 4K 60. How long is the cable? If it’s super long I could see the signal degrading enough.
@Level1_Amber They are all Cooler Master Tempest GP27-FUS screens. The Cooler Master support itself is pretty useless so far unfortunately. They are telling me to use HDMI which is of course not possible if I want to continue using my L1T KVM switch (what I definitely want to do )
Any help is highly appreciated I don’t know a place that has more knowledge about these things than this forum.
Plug the adapter directly into the output DP signal, then plug a high-quality HDMI cable in to the other end out to the monitor. Going DP → HDMI shouldn’t be difficult. You should also be able to do the 4k/60 you’re wanting.
@GigaBusterEXE I agree in general, but this Cooler Master Screen seems to be pretty solid for the price tag it has. There were firmware issues in the beginning, but the picture is really good. I ordered a single one first to test it myself, before getting 2 more. Regarding KVM: It doesn’t make a difference. The L1T KVMs are basically just „cables“. They don’t mess with the signal (besides from probably very minor signal degradation).
@Level1_Amber DP->HDMI won’t work sadly, because only 2 DP ports can be used if the monitors on these ports are using DSC. I didn’t test yet, if I can use 2 DP ports and 1 HDMI (with HDMI->DP adapter possibly), but from what I read even that is not possible. The GPU seems to have 4 internal „heads“ (1 per port), but the NVIDIA DSC implementation uses up 2 heads per port which means I’m limited to 2 ports in total (no matter if DP or HDMI) unless there is only 1 DSC monitor connected.
@GigaBusterEXE Yes, but that does not help. This single monitor does not use DSC in that case, but the GPU can not serve a signal to it, because the 2 other screens will still use DSC which will cause the DP port 3 and the HDMI port to be disfinctional due to this crappy NVIDIA limitation. In other words: Only 1 of my 3 screens can use DSC. 2 screens with DSC would be possible, but then I can’t connect a 3rd one at all.
@GigaBusterEXE Ahh right, using at least 2 DP->HDMI adapters would be a valid solution, thanks! The primary screen could still use a regular DP+DSC connection for high refresh rates, VRR, etc.
This would limit me to 4K60Hz which is ok for me for the secondary/tertiary screen. 90Hz would be a little better (DP1.3/1.4 wo. DSC), but for now this should work.
Unfortunately there seem to be an issue with this adapter and/or my setup. After each reboot/hibernate at least one (mainly both) of the HDMI monitors is not recognized correctly anymore. Device manager lists it as nvfailsave, the resolution is set to 640x480 and all custom monitor configuration (monitor placement, scaling, etc) is lost. This can be fixed by re-plugging the screens (or switching to a different source using the L1KVM and back to the previous one).
Any ideas besides trying a different adapter (Amazon is going to kill me for all the display related stuff I returned lately )?
Have you tried updating your graphics driver? There’s a whole article about this happening on certain driver versions on the nvidia forum. As far as I can tell, this is a driver issue and not an adapter issue.
@Level1_Amber I’m running a pretty recent “Game Ready” driver 537.13. Latest one is 537.42 which I’ll try now.
In my case I think it’s not the driver, but the DP->HDMI adapter unfortunately. I’ll as well ordered another pair of DP->HDMI adapters for testing purposes.
For anybody else with the same initial problem (GP27-FUS and DSC):
I’m in contact with Cooler Master support and they might add an option to disable DSC (switching to DP1.2 mode) to the OSD. However, they did not officially accept or reject this proposal yet.
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