alistair.priest :
I am having the same issue. Funny enough it only happening on my samsung series 9 and not my series 6. Both new and 4k capable. At times i will get the signal to work correctly, other times it flashes between singnal and no signal, and other no signal at all.
Also. I am running this signal over hdmi extenders on cat 6.
So frustrating.
Yeah HDMI 2.0 cable did NOT help here, bought 150 euro cable (HDMI 2.0b , HDMI Premium certified , guranteed to work with 4K chroma 4:4:4 @ 60Hz) it even has LED indicators if signal goes through and yes, UHD led is lighted on cable, but alas, NO SIGNAL from Samsung "Smart" UHD TV 8000 series "Premium" panel. What a joke.
I see BIOS screen perfectly well and the login screen, but after login, computer reboots itself (only when connected to Samsung UHD, never otherwise)
Picture shows very well on my old HD plasma and Dell monitor.. no matter which cable i use with them. Just no way to work with Samsung "Smart" UHD TV (real smart this TV ffs...)
GFX card is 1080 Ti btw should work nicely. Tried to run DDU couple times and different Nvidia driver versions, no use.
Tried to use Club3D DP - HDMI adapter, no use
Tried to enable internal graphics if problem is Nvidia, and plug hdmi there : no use
Propably the only solution that i have not yet tested is the one marked as "solution" here : format my drive and install Win 8.1 again, which is ridiculous solution, but cant think of anything else besides that what i hadnt already tried...