G7 7790 Internal display and HDMI are very slow, DisplayPort is fine
So, I have a Dell G7 7790 with an GeForce RTX 2060 card. I am able to run pretty much whatever I've tried on an external monitor with the Display Port smoothly. When I try to run the same games without an external display, the framerate drops significantly (upwards of 60FPS to 10 or 20). I've seen that the internal display is expected to be a little worse (I don't get the technical reasons for it, but that doesn't matter). Regardless, the HDMI should be able to run 1080p @ 60FPS just fine.
When running without an external monitor, the NVIDIA card is in use, and the Intel card shows very low utilization. The HDMI port also behaves like the internal display, even though it shows as connected to the NVIDIA card in windows advanced display settings.I get nice framerates on menus and things, but as soon as it gets to more intensive graphics, the HDMI drops to 10-20FPS. If I run the same test on the DisplayPort, I get consistent >=60FPS.
This implies that the card is not just underpowered, it is capable of rendering the game at 1080p@60Hz, but only on one of it's connected interfaces (The HDMI is connected to the NVIDIA card). For some reason, the card throttles itself when using the HDMI. Additionally, the HDMI port/cable/display are capable of running at 60FPS because animated menus in games and videos run fine.
I have updated both NVIDIA and Intel drivers recently.