However, the HDMI port still works. And playing FPS games on a 60Hz 17" LCD monitor with a line down the center is no fun. While my severely outdated desktop (2008 C2D E-8400 / 4GB RAM) remains dead with a failed motherboard my only choice is this laptop for general use and gaming. I don't really have the option to replace the desktop or the laptop with something modern so getting a new monitor is a step-gap. My monitor of choice ended up being the ASUS MG279Q.
It's been asked numerous times on various hardware and gaming sites whether or not you can use a 120Hz / 144Hz monitor at those speeds over HDMI (but which version?). Most of the time there's an ambiguous answer leaning towards "no", but since you sometimes see "yes" it might work, right?
HDMI 1.4 supports a maximum resolution of 4K or 4096x2160 pixels, most of the time at 30hz, but some have managed to get an image working at 60hz with NVIDIA's compression technology. So why wouldn't we get a 720p image over the rate of 60Hz? It seems there's arbitrary information stating that HDMI has strict caps on the refresh rate for each resolution, but there are multiple revisions of the standard.
In my case, I obtained an ASUS MG279Q monitor with a maximum specified refresh rate of 144Hz, with connections for HDMI (2), DisplayPort (DP) and Mini-DP. It's generally known that DP supports most ranges of configurations these days and is recommended for higher refresh rate support. This laptop only has HDMI output, and is specifically version 1.4.
From the HP Maintenance and Service Guide
Upon plugging this monitor into the laptop, I was presented with a maximum refresh rate of 120Hz at 1080p in the Windows 10 Intel HD Graphics Control Panel. I was very content seeing this as I had a strong feeling it would allow me to use the 120Hz setting at a lower resolution (something I could get most games to play at with a consistent frame rate) and a possibly higher refresh rate if I wanted to do some more tinkering.
The laptop supports a hybrid display adapter containing an Intel HD 4600 video adapter and a Geforce 740M. Most 3D acceleration is handled by the 740M.
By default, the monitor only reports a maximum of 120Hz at 1080p (at 1440p I am limited to 60Hz.) I do not have a way to test if the reported information is the same over DP at the moment. Setting the display to 1280x720, I was still limited to 60Hz so there's a mismatch of supported refresh rates being reported. In order to do further testing, I needed to use the Custom Resolution Utility (CRU) to add entries to the resolution and refresh rate lists that don't normally appear. After configuring CRU to add a new entry for 720p @ 120Hz, I restarted the graphics driver using the CRU utility and I had a new entry in the display options. I was able to play Quake Live on this setting and reached a consistent 120FPS.
Next, I created another custom entry with CRU for 1280x720 @ 144Hz.
Again, after restarting, I was able to select this new resolution and refresh rate.
720P @ 144Hz over HDMI 1.4
Unfortunately, I do not have any games immediately available that I can play with a consistent 144+FPS rate. Quake Champions only supports the default maximum resolution at 60Hz in fullscreen mode, but does allow borderless windowed mode to match the Windows desktop refresh rate (with and without V-SYNC) so in specific situations, I was able to see very smooth game play.
At this point, we can see that there's likely a few things going on here that allow 120Hz / 144Hz refresh rates on older hardware. My only variable that is available to test would be the cable itself. Could older HDMI cables that do not support the 1.4-2.0 standard cause issues?
For the sake of testing, I used two different HDMI cables, one is a generic cable manufactured around 2009 and the other is a cable by BlueRigger which is specifically labeled to support HDMI 2.0 (and prior versions). The BlueRigger Basic cable is linked through my Amazon affiliate program.
BlueRigger Basic HDMI 2.0 Cable
The older generic cable would not work at 120Hz or higher. Cable standard certifications do matter.
In order to get 720p resolution at 144Hz (or 1080p @ 120Hz), we need a few things working together:
- A display adapter with a minimum version of 1.4
- A monitor supporting HDMI 1.4 and a 120Hz / 144HZ / + panel
- An HDMI cable certified for 1.4 and above.
- Custom Resolution Software (CRU - Windows) and manual entries for these resolutions
Out of curiosity, I attempted to create custom refresh rates of 100Hz, and 120Hz at 1440p. Unfortunately, neither worked, so there is some point in this process (possibly the Intel HD4600) limiting the maximum resolution and rates. To push things a little further I configured 1440p at 65Hz and this was successful.
In the end, the answer is yes, 120Hz / 144Hz works with an HDMI cable (depending on your hardware.)