The original Dr HDMI is an HDMI 1.4a device. The specified video support lists 2K, WUXGA (1920×1200) and 1080p60, with single-link 225 MHz and 2.25 Gbps video bandwidth.
What does "2K" mean here?
For this older product, 2K appears in the historical product specifications alongside WUXGA and 1080p60. It should not automatically be read as a promise for every modern 2560×1440/QHD timing. For compatibility, the specific timing and the complete HDMI chain are decisive.
Not a modern 4K/8K version
This site is about the original Dr HDMI. It is not the same product as the later Dr HDMI 4K or 8K models and is not intended for HDMI 2.0/2.1 features such as 4K120 or VRR. Compare the three models →
What fits within 225 MHz?
Whether a video format can pass through an HDMI 1.4a chain depends on the TMDS clock it needs. That clock equals the pixel clock of the timing, multiplied by 1.25 for 10-bit and by 1.5 for 12-bit Deep Color. The 2.25 Gbps HDfury specifies follows from the same limit: 225 MHz times 10 bits per TMDS channel. The standard timings below are for comparison.
That is why HDfury lists 1080p60 at 12-bit as the maximum, and why 4K is not possible with this model. Whether a particular combination works in your chain also depends on what the source, display and intermediate equipment support.