It depends on the motherboard. Some boards allow up to 2200mhz ram on P67. Keep in mind though, that you shouldn't run RAM over 1.58V with these chips. That is the max amount of voltage that is safe for the integrated memory controller.
You're going to have a hard time buying ram at those super high frequencies without exceeding the max recommended voltage. 1.5V is what is recommended, and the fastest you can get at that voltage is 1600mhz (stock speed).
