Ok, I misinterpreted your comment. The pros and cons of eDRAM vs ZRAM is basically the same thing - a dedicated structure for the storage capacitor in conventional eDRAM. The pro is that each cell stores more charge than ZRAM can and allows more speed and margin. The con is the cell cap requires special process steps which makes it more expensive per wafer. It is also hard to build eDRAM cell caps in a process along with high performance transistors needed for MPUs although some companies have found ways around this.