i have a vengeance low profile 8gb 1866mhz ram but im running it at 1600mhz. i tried 1.5v and 1.55v with 1866 option in bios and got a failed message. i have the m5a99x evo r2.0 with fx 6300 at 4.5ghz. anyway i can run it at 1866?
With a 6300 prob better off trying at 1600, generally only the upper tier FX CPUs can handle 1866, can try enabling DOCP, EOCP or XMP is your mobo has any of those options and selecting 1866