If you add 3200mhz RAM then it will automatically underclock itself to 2400mhz .
Can I use 3200mhz RAM in 3600mhz motherboard?
RAM that is rated at 3600 MHz will definitely not be hurt by running at 3200 MHz instead. In fact, if you don't enable XMP, then the ram will probably run by 2133 MHz by default as that is the highest “official” speed that the JEDEC standards support, and that would be just fine too.