Thank you so much for taking the time to look into my issue! Because of the location where I work, the system interface in the screenshot is in Chinese. If there is anything you don't understand and need translation for, please let me know!
My device is a Lenovo ThinkBook 16 G6+ IMH laptop, equipped with an Intel Core Ultra 5 125H processor and only an integrated graphics unit (iGPU). When I connect it to an AOC 24G2 monitor (which supports 1920×1080@144Hz) using an HDMI cable that supports HDMI 2.0, via its HDMI port (Lenovo states that it supports HDMI 2.1 TMDS), I am only able to select a refresh rate of 120Hz and not 144Hz. It's worth mentioning that when I use other devices to connect to the same monitor via the same HDMI cable (for example, an NVIDIA GeForce RTX 4060 Laptop dGPU or an AMD Radeon Vega 8 iGPU), the 144Hz refresh rate is always available and works perfectly.
I have tried installing the graphics drivers provided by Lenovo's official website, as well as the latest version of the graphics drivers from Intel. I even attempted to update the BIOS of my laptop, but the issue still persists.
Earlier, I attempted to connect to another UWQHD monitor (AOC CU34G4Z) using a higher-speed HDMI cable that supports HDMI 2.1. This monitor supports up to 3440×1440@240Hz with RGB 12-bit color depth and works well when connected to an NVIDIA GeForce RTX 4060 Laptop. When connecting the aforementioned Lenovo ThinkBook with the Ultra 5 125H processor, I can smoothly select all resolutions from 1920×1080 to 3440×1440 and switch between color depths of 8-bit, 10-bit, and 12-bit. However, regardless of the resolution, the maximum refresh rate is only 120Hz—even at 1280×720 resolution!
Is this because Intel's integrated graphics only support display signals that comply with the VESA standard (such as CVT-RB) when connected via HDMI? Should I consider abandoning my HDMI port and switch to using DisplayPort 1.4 to connect my monitor instead?
I'm really puzzled, and would be extremely grateful if you could help me resolve this issue!
Link Copied
HDMI 2.1 TMDS = HDMI 2.0 = 18 Gbps = 600 MHz TMDS, that's right.
From experience with other cases, it seems to me that the HDMI ports on laptops with integrated Intel graphics often only output signals with CTA-861 video timing. CTA = Consumer Technology Association, it defines the standards for HDMI video transmission in consumer electronics. 120 Hz is the maximum there so far. However, that doesn't fit with the fact that the HDMI port, as you describe, outputs 3440 x 1440, because there is no CTA-861 video timing for that. In any case, this behavior depends only on the graphics driver; the hardware itself can actually do everything.
If you want, we can go into the analysis in more detail, but since you are asking about the best possible connection, I would recommend running a monitor via the DisplayPort protocol.
DisplayPort 1.4a HBR3 (over USB Type-C) = 32 Gbps
Very high modes are possible with Display Stream Compression (DSC), as was the case with the Nvidia GeForce RTX 4060 laptop GPU you tested: 3440 x 1440 @ 240Hz 12-bit = 194% HBR3 (with DSC ... OK)
Please use one of these cables for your laptop, it's the best option available:
- Zeskit MAYA 8K Bi-Directional USB-C to DisplayPort 1.4 Cable
- Club 3D USB Type C Cable to DP 1.4 (CAC-1557)
- Cable Matters USB-C to DisplayPort Cable - 8K Ready (201036)
- Cable Matters Premium Braided USB C to DisplayPort 1.4 Cable (201336)
You can of course use a different brand, just make sure it's a bidirectional cable with HBR3 (32 Gbps) support. The AOC 24G2W1G4 monitor only needs HBR2 for 1080p @ 144 Hz, but then you're future-proof.
