The 2 sets are built 10 months apart
Manufacturers often change the components/design/programmed settings over such a long time period, even while keeping the same part number.
and seems like overclocking has to be reduced to make them run.
I don't quite understand what you mean by this.
It also boots in 333mhz if I set it to auto on the memory divider so I need to manualy change it to 400
This is often normal. What model number(s) HyperX do you have?