GPU evaluation may consist of:
- Decoder (dual HD video stream, MVC, 4K, etc.)
- Post-processors (typically measured with HQV Benchmark). Intel uses ASICs (application specific IC) + driver, while AMD / NVIDIA is likely to use general-purpose stream processors + drivers. They usually work under EVR (and other video renderers in some cases).
- Good for madVR? madVR has its own post-processing algorithms (i.e. PQ is independent of the graphics card) that are executed in stream processors. Well-edited/encoded videos (usually delivered in optical media) don't need much of post-processing and madVR shines here for several reasons (although it's still in beta stage).
- Miscellaneous aspects such as stereoscopic 3D (i.e. Frame packing) output, 4K output, HDMI audio (88.2kHz? dual audio stream? etc.), refresh rate (how close to 23.976Hz/59.94Hz), black levels (supporting both of full and limited?), intuitive/working GUI, hardware encoder etc.
(I have acquired enough knowledge on individual cards to write an article.) As for madVR, there are only two criteria in choosing a graphics card:
1. Copy-back / upload speed
2. Rendering engine (stream processors).
So simple. NVIDIA (GT 430 DDR3-1600 or higher) is the best in both. HD 6570 is also good (except for slow copy-back/upload speed for 1080p60 contents). The latest HD 7750 is fast enough. AMD Llano has the same problem as HD 6570 (and even worse). I expect AMD Trinity is as good as HD 7750. Intel iGPU lacks enough rendering engine. Precisely speaking, they (except for Intel HD 4000) are all good for films, but none of them is good for videos. Intel HD 4000 is good for all contents, except for 760p60.