With an active DP to HDMI converter you can reach the DP limit.

HDMI may well have a larger peak to peak voltage than DP and have a fixed 'slew rate' that is limiting the signalling speed. There's a lot of intelligent multiplexing that goes into modern graphics and the chip may well simply switch to a 'slower' HDMI mode or the signalling buffers inside the GPU may simply be slower for HDMI signals. I would expect that case to function at the HDMI speed. DP can also 'fall back' to HDMI when used with a passive (wire only) converter. From experience I can say that HDMI 1.4 definitely can handle 120Hz, so that fits well with theory.ĭisplayPort and HDMI are also separate and work on separate protocols. If you have 1920 x 1080 pixels, which is 2,073,600, slightly under 1/4 of the full 4K resolution, then it should be capable of approximately 120Hz. Is the maximum number of pixels that can be thrown per second. mathematically 4096 x 2304 = 9,453,568 pixels per frame and it can then put out 30 times that every second for approximately 300 million pixels per second. The maximum refresh rate shown is the 'pixel clock' rate.

Intel graphics hd 630