My 2c: don't run multiple sticks at above 200-250mhz. the table shows that 250 mhz is already exceeding superpag's 2A/slot.
If you look at the specs (according to Amazon, so I guess a grain of salt) each port should actually support 2.4A/slot. That means (in theory) we should be able to go up to 275Mhz. Of course this assumes that the hubs can handle 100% load all the time...