All, I have confirmed the supported resolutions and refresh rates for HD 4000. This issue is a hardware limitation of the HD4000 chipset. It does not support a pixel clock greater than 225MHz on HDMI. The following are the supported rates.
DVI :
Intel HD4000 Max Pixel Clock supported on Single Channel DVI is 165Mhz. So max supported is 1920 x 1080 (60p Hz) On DVI
HDMI :
Intel HD4000 Max Pixel Clock supported on HDMI is 225Mhz. So max supported is 1920 x 1080 (60p, 85p) On HDMI
Note : 2560 x1440_ (60 Hz) is not supported on HDMI as it Exceeds the max Pixel Clock supported by our Intel 4000 Hardware ( 225Mhz)
Driver will enable and support 225Mhz based on HDMI Panel’s (HDMI Registration ID supplied by panel )
DispalyPort :
Intel HD4000 Max Pixel Clock supported on DisplayPort is 348 Mhz
So, 2560 x1440_ 60 and 2560 x1600_ 60 is supported on DisplayPort Interface only.
Thanks
Robert