It depends more on the quality of the IMC on your 1600 than the motherboard. Some non-x chips will never get to 3200mhz (this was a quote from support in a motherboard forum but I can't find it now).
My 1600 wont go above 2800, even with looser timings, 1.4v on the ram and 1.3v on the soc. Originally I had the gigabyte b350 gaming 3 at 2666, returned it due to ram speeds and took the asus b350 prime and got the same result. The latest beta bios lets me get to 2800.