TPS53689T: SVID Decay issue

Tool/software:

Hi TI experts,

With TPS53689T+CSD95560 design for Intel CPU, the VID_Decay test only pass with Decay_DCM bit enabled.

Questions:

1. With Decay_DCM enabled, is it effective ONLY when CPU enters Decay mode?
2. If yes, at which condition the CPU will enter Decay mode? Will it impact VRM performance in Decay mode?
3. If no, any other impact to VRM performance during normal CPU operation?

Thanks

Neo