I doubt it. R7s have already shown the ability to run IF speeds up to 2000 MHz, stable. The problem is the IMC and/or RAM ICs can't handle DDR4-4000 at the present. There may be some bizarre technical reason why they are unable to choose different ratios, but in terms of raw speed, the present IF implementation CAN handle such speeds. Plus there's no reason why they couldn't fix that technical limitation, if they so chose.
Sorry, I should have said DF/DRAM speed ratio.