8K 240Hz Mode Doesn’t Work On Samsung Odyssey Neo G9 Monitor Coupled With GeForce RTX 4090

A review by South Korea’s QuasarZone media channel emphasizes that the upcoming ultra-wide Odyssey G9 Neo monitor from Samsung is exclusively compatible with Radeon RX 7000 GPUs.

Samsung’s flagship offering, the Odyssey G9 Neo, features a 32:9 aspect ratio, DisplayHDR 1000 certification, and a 1000R curvature. Notably, it offers a dual 4K resolution (7680×2160) at a 240Hz refresh rate, provided the GPU can handle it. Unfortunately, only a select few GPUs meet this requirement.

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The Odyssey G9 Neo was introduced shortly before the launch of the Radeon RX 7800 series, being touted as the first monitor to embrace the DisplayPort 2.1 standard. However, the uptake of DisplayPort 2.0, which was later upgraded to 2.1, has been sluggish, to the point that NVIDIA chose not to incorporate this standard into their RTX 40 series almost a year ago.

QuasarZone’s tests have uncovered that neither NVIDIA nor Intel graphics cards can achieve a seamless 7680×2160 resolution at a 240Hz refresh rate using their HDMI 2.1 implementation, despite utilizing the entire 48 Gbps bandwidth. The precise cause of this restriction remains uncertain, but there is speculation that NVIDIA GPUs may lack the necessary Display Stream Compression (DSC) pipelines to handle it.

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It’s important to highlight that an 8K/120p stream with Display Stream Compression (DSC) necessitates 32 Gbps. The Odyssey monitor uses only half of the pixels (it’s dual 4K, while 8K is quad 4K), but it doubles the refresh rate. The precise reason why the RTX 4090 cannot achieve a 240Hz output remains unclear, but one Redditor speculates on a possible explanation:

“DSC uses display pipelines within the GPU silicon itself to compress the image down. Ever notice how one or more display output ports will be disabled when using DSC at X resolution and Y frequency? That is because the GPU steals those display lanes to process and compress the image.

So what does this mean? It means if the configuration, in silicon, does not allow for enough display output pipelines to be used by a single output port, THAT is where the bottleneck occurs.
But there are deeper things with DSC than bandwidth. There is also how the compression is done, both ratio wise and slice wise. DSC will happily allow a 3.75:1 ratio for 10 bit inputs as long as the driver/firmware of the GPU allows for it (as it is part of DSC spec). Nvidia’s VR API tools for developers only allow for a max of 3:1 it should be noted.

The allowable slice dimensions and count (how the screen is divided for compression) also determines how much throughput can be achieved (by way of increasing parallelism during compression). This is a silicon/hardware limitation, although again, could be limited by firmware.


The Samsung G9 monitor illustrates both the potential drawbacks and limited concerns regarding NVIDIA’s choice to skip DP 2.1 support. Firstly, the Odyssey G9 Neo comes with a steep price tag of $2,499 in the US, exceeding the cost of even an RTX 4090 GPU. Additionally, the NVIDIA RTX 4090 card doesn’t encounter any issues when it comes to handling high refresh rates at 4K resolution or the increasingly popular ultra-wide DQHD (dual 1440p) format that gamers are showing more interest in.

Via Videocardz

Picture Credit: QuasarZone