There are card-sized SBCs with the Intel N100. Very cool.
https://news.ycombinator.com/item?id=41007348
Also found this geerling review [0] today (which mentions yours as well) which does list slightly higher numbers but he notes that he used actual thermal paste to get better cooling with that gaping heatsink box, which seems to have helped on at least a few fronts. If your cooling theory about the G2 holds, then the memory might be overheating on the X4.
I suspect this is just a matter of timing tweaks in the BIOS.
That aside, it does have some impressive specs (twin ufl ports for external wifi antennas are dope), even though the LPDDR5 is bottlenecked by a dumb 32 bit bus. I was looking to buy one the other day but it's currently out of stock everywhere and the 12/16 GB versions that would be most interesting are nowhere to be seen, so for now it's not really something anyone can buy.