First of all I want to say a massive thanks to
for all his efforts and informative posts on this forum and
for all his efforts with madvr.
Through past posts its been determined than intel integrated graphics provides the best dxva scaling as intel has dedicated hardware scaling circuits unlike nvidia and amd. Intel also has dedicated de-interlacing hardware meaning it won't affect rendering performance with madvr.
With my current graphics card, I've set-up madvr with hot-keys for the different luma up and downscale algorithms and when I pause a frame I can switch between them. It has already been determined that AMD uses bilinear to upscale and from my comparison this appears to be the case. Whats noticeable is how much this softens, blurs and degrades the picture. It makes 720p on a 768p screen look awful. Unfortunately I can only take advantage of madvr using mpc-hc which is unable to stream from youtube or vimeo. Using an Intel IGP, while I wouldn't be able to gain access to other madvr features such as error diffusion or svp, and better scaling algorithms such as jinc or nnedi, for all other sources of video that can't take advantage of madvr that is anything online based (netflix, vimeo, youtube, dailymotion, hbo go, bbc iplayer etc), the results for upscaling would be much better.
Intels IGP however isn't powerful enough to run jinc for luma and chroma, at least with anti-ringing, and for upscaling 1080p to 4k. I would require a dedicated graphics card from nvidia or amd which is powerful enough for luma doubling or at least jinc3+ar luma+chroma. Since no motherboards have hdmi2, and displayport can't output 23.98hz,24hz,29.97hz, hdmi would also need to be used, so hopefully a graphics card in future will have hdmi2 and hevc decoding. A powerful graphics card is also very power hungry.
An ideal solution would be to use the IGP from intel a majority of the time, but I believe so long as a graphics card is installed it'll draw power? The 750ti according to techpowerup idles at 4w. If I could connect the same tv via the motherboard and graphics card and switch between the two depending on the situation without having to restart, but during use that would be ideal.
Does anyone know about the possibility of connecting the same display via graphics card and motherboard and hot switching between the two? Or if it's even possible to use the intergrated graphics once you've installed a graphics card?