https://www.wepc.com/reviews/ddr5-latest/
Clock for clock at 3200MHZ DDR5 is 36% faster than DDR4. However that is measured bandwidth. As correctly @4K8KW10 said, we need to look at latencies also.
It would be pointless to have 120ns DDR5 ram, when we get lower than 60ns with DDR4 these days.
It will also come at quite a premium price wise for what will be very basic modules compared to what will come a year or so later when it's fully up to speed.