That's basically the max supported. But it won't matter that much. I don't think, regardless of advertising, that you can make the whole system run that fast.
It says that FSB is 1333/1066 MHz. That's FSB freqs of 333 and 266 MHz. That corresponds to memory speeds of DDR2-667 and -533. And Core2 systems just do not benefit from overclocking the memory.
Then there is very little true DDR2-1066 RAM. Most of it is DDR2-800 RAM that has been tested to run at the higher speed by increasing the voltage and relaxing the memory timing.
Save your money and buy good DDR2-800 RAM.