XG3220 4k 60Hz -> 1080p 120Hz

[itsmeuy]

I hope someone can help me with this issue. I recently bought a Viewsonic XG3220 which natively works at 4k@60Hz. If I look at the manual (https://www.bhphotovideo.com/lit_files/397638.pdf), it states that 1080p@120Hz is supported. However, I can't get ANY resolution past 69Hz to work. No matter how small the resolution is I always get a black screen. I'm connecting the display using the official displayport (1.2) cable to a RTX 2070 (latest drivers) and creating custom resolutions using the NVCP. I've tried all the standard timings options with no success.

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What do you think could be wrong?
Thanks for the help!

[Chief Blur Buster]

Try the numbers found at True 120Hz from PC to TV.

Also test a Vertical Total of 1125 for 1080p, which is more standard for televisions.

What you'll want to run is exactly four times the Broadcast ATSC 1080i pixel clock, and keep the same totals, except use progressive + double Hz (which is exactly 4x the bandwidth of the old 1080i standardization).

[itsmeuy]

I really appreciate your reply! Unfortunately trying those numbers using either NVCP or CRU gives me an "out of range" message. BTW, I'm using "display scaling" in NVCP which I think is the correct way to avoid "sending the full native resolution (4k)" which of course wouldn't work at 120Hz. Is that assumption correct? Sorry, I'm pretty new at all this stuff but trying to learn what's going on behind the scenes. Thanks again!

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