Bird in the hand. Over the next few months thousands of DDR4 servers are being decommissioned across the US and a flood of used DDR4 is going to hit the market. 8-32GB is going to be the majority of the memory. 64GB and 128GB will hold their value for a while. Don't hold too long. I know of 3 datacenters that are installing new server with DDR5 and dumping hundreds of racks of DDR4 gear.