4k TV strange behaviour at 1440p - please help

[clintay]

Hi, i was hoping someone could help me:

I have a TCL 43p6us 43" 4k tv that im trying to get to run at 2560x1440 at a higher refresh rate....ideally 120-140hz (GTX 1070 graphics card, windows10, tried many different display driver versions)

This tv/monitor is native 4k 60hz but i have succesfully run it on 1920x1080 at up to 235hz....it seems it will run anything at 1080p as long as its under the Hdmi2 600mhz pixel clock limit. Ive tried this on hdmi to hdmi and also DisplayPort-active adapter-HDMI... ive also tried both HDMI ports on the TV with the same result.

When i set it to 2560x1440 using CRU it does this strange thing where part of the screen is duplicated on the right side (see attached pic). Ive tried the different timing presets and they all do the same (if they work)

The odd thing is i can set it to 2560x1440 using NVIDIA control panel custom resolution and even up the refresh rate to 70hz and it will work (but it is reported as 2160p by the TV.... see attached pic) but as soon as i go over that it either jitters a fair bit or does the same duplication thing on the right side of the TV.... seems like its random. Using CRU i can never get it to display 1440p properly not even at 60hz.

I can get it up to 120-140hz on 1440p using CRU or NVIDIA control panel but it always shows that duplicate section on the right hand side..... if i can somehow get rid of it that would make me very happy

Anyone seen anything like this before? Any ideas? Should I be trying custom timings? (ive played around with them but dont know what im doing)

Thanks in advance

[ToastyX]

It really looks like your TV doesn't like 2560x1440. Keep in mind that the NVIDIA control panel creates scaled resolutions if the display mode doesn't match the active pixels.

[clintay]

Thanks for the reply... Yes it seems when it displays properly at 1440p (at 60-70hz) windows display properties shows the active pixels still at 3840x2160 (in advanced properties) so you are correct it is being scaled by NVIDIA control panel. Every time it does the weird duplication artifact the active pixels are shown as 2560x1440.

A bit disappointed I can't get it into the 1440p 120hz sweet spot for gaming..... It's a.decent monitor otherwise with low input lag.