These new chips are manufactured on a 1z nm class production process but so far we don't have a lot of technical details. The first memory module to use the A-dies is the Samsung M378A4G43AB2-CVF, a single DIMM DDR4 module with a capacity of 32GB, a frequency of 2933MHz and CL21-21-21 timings.
This particular offer isn't something to be excited about as the frequency is good, but the timings are quite high for that speed. Given that we don't know where the A die is targeted at, we can speculate that its current aim is at mid-tier systems, where the mediocre performance is okay and the system isn't suffering (performance wise) because of it. Nonetheless this find is quite interesting as it gives first hints at what can we expect in therms of future A die DRAM offerings.TechPowerUp speculates we may see better offerings over time. The site recalls that it took some time for B die as well to get to where it stood before it got discontinued.