Hello i have dv6 with switcable graphics. It has intel HD 4000 + radeon 6770m 1 gb VRAM, 8 GB system Ram, with i7 CPU. I understand from internet sources that the max resolution that 6770m can support is 2560 x 1600. i got a 4K display, when i connect and enable only the 4K display, the max resolution option available is 2048 x 1280. the 6770m is the active graphics. I tried to do the registry edit trick but still 2560 x 1600 option does not become abvailable. I tried to add a custom resolution thru the intel graphics app but it gives an error that this resolution excceds the max bandwidth. I have a feeling that the radeon itself can support 2560 x 1600, but may be because Intel HD 4000 cant, its now showing me the higher resolution. I tried to disable intel HD 4000 from device manager but then the grahics stopped all together. Is there any way to enable 2560 x 1600 on this laptop?
This is just a guess, but download this https://www.monitortests.com/cru-1.3.zip, and make a custom resolution for the TV with 3840x2160@30hz. You could also try using the amd pixel patch if the bandwith is exceeded. I have gotten my HD 5770 to output 4k 30hz with HDMI using CRU method.
