>If it doesn't overclock, you RMA it

Overclocks are explicitly not covered by warranty.

Yes, Intel and AMD and mobo vendors all say overclocks "may" void warranty and in general they have honored warranties for overclocked hardware, but the official and legal position is that overclocking is not covered by warranty.

>It just doesn't fit the facts to say that you shouldn't expect 5400 Mhz ram to work at 5400 Mhz

You can certainly try RMAing the RAM with the RAM vendor since they sold it for whatever frequency they marketed it at. But as far as Intel and the mobo vendor would be concerned, an overclock is beyond the purview of their warranties.