Display does not match the intended proportions.
Display does not match the intended proportions.
Hi. I recently added a second monitor that’s 21:9 at 3440x1440 resolution, while my main display remains at the standard 2560x1440 16:9. I’m connecting both using HDMI cables—my main monitor works perfectly, but the second one isn’t showing correctly. Windows interprets my second screen as 4K and, by default, adjusts its resolution to 3840x2160. This forces it to fill the screen but stretches it to fit the 21:9 aspect ratio. When I set it manually to 3440x1440, it stretches even more and shows black bars at the top and bottom. Since my DP cable isn’t long enough, I’m limited to using just this one DP-to-HDMI adapter. A regular HDMI cable works fine, but the one I have is only a bit long and reaches across my chair. Also, it operates at 50 or 60 Hz while the monitor supports 100 Hz—possibly the cable isn’t the issue, but the port specifications or HDMI version. I have a DP 1.4 port, and if needed, I could purchase a longer cable. Image should display at 3440x1440, but Windows claims the active resolution is 4K. Could this mismatch be causing the problem? Also, at 2560x1080 with 100Hz it works well, but at lower refresh rates it shows the same stretching issue. Maybe a 100Hz 1440p cable would help.
You're questioning whether the cable itself is the issue, not just your setup. I'd suggest it's likely the cable, opt for a better one. With 50 Hz and chroma subsampling (YCbCr420 instead of 444), it clearly indicates insufficient bandwidth. Also, refer to this guide: Look at the specific table and the 3.5K row, column for Type 2 at 50 Hz.
I’ll check a different cable if possible. I was able to get it running by setting the display adapter to 3440x1440@50Hz on the properties page, though a full 100 would be better. Also, do you know if a USB-C to HDMI adapter matches my resolution? It would be cheaper to use a smaller HDMI cable and just plug in the adapter instead of buying a large DP. Edited March 10, 2024 by iGPR3
Usb-c's alternative function is typically display port, meaning the same constraints as dp to hdmi should be followed.