I'm having the same issue. I am trying to plug the HDMI cable into an external display, and it will only use the integrated Intel HD 4600 display adapter. I have messed with the nVidia control panel, and tried everything on here, but it won't seem to recognize the nVidia card through the HDMI. The graphics are very bad and laggy. Also using a Lenovo laptop, with a GT755m.
I have also tried disabling the Intel HD4600 through the device manager, then plugging in the HDMI. In this case, nothing appears.
Also, I used the nVidia settings to make sure the .exe for a test game was set to used nVidia, thinking that maybe the display would go through the Intel chip, but nVidia card would get used for the game. I notice no improvement, and the graphics and lag are terrible.
I saw another forum that found uninstalling and reinstalling the nVidia drivers worked, but I would like to avoid that.
Also, someone suggested going through BIOS, but I don't know how to get into Lenovo BIOS.
I know the gt755m card is advertised as having HDMI capability, but it looks like the port goes straight into the mobo, rather than the video card. Is it just impossible to get the GPU to power the HDMI output?
Update: Went ahead and clean installed the drivers for nVidia and Intel. Graphics still terrible. Also compared the graphisc before after after disabling the gt755m. Completely the same either way.
Another update: I noticed there is a VGA port that DOES come directly out of the video card. I tried plugging that in and the same thing happened...It automatically switches to the intel HD4600, and the graphics look awful. So it seems the problem is not HDMI specific.
Thanks for any help on this.