Memory Speed Suddenly Dropped

[Raptor1966]

Hi ihave been using 32gb of kingsteen beast 2400mhz memory at 2400mhz with XMP Profile 1 for months with no issue on my maximus formula vi

all of a sudden my pc will not boot in to windows at 2400 but will when the default 1333mhz is set in the bios

i did a memok, but when i go in to the bios it shows the xmp profile is active @2400, but on the post screen it shows 1333mhz.

the only change to my system recently was the upgrade to a strix gtx 680.

i have updated the bios for both the graphics card and motherboard

i have done numerous f5 bios defaults and numerous cmos resets

what is the proper prcedure for clearing the cmos

when i got this memory first i had issues getting it going, but it sorted it self out

[NemesisChild]

It depends what board you have, most by moving the CMOS jumper pin to the "short" position.
What is the speed indicated via CPU-Z?
Don't use the XMP profile for now, manually input your base memory timings, frequency, and DRAM voltage in the bios.