i bought 4x4g Ballistix Tactical Tracer 8GB Kit (4GBx2) DDR3 1866 MT/s (PC3-14900) UDIMM 240-Pin - BLT2CP4G3D1869DT2TXOBCEU i wanted to run at 1866mhz so i went into bios and set the xmp profile which takes the memory from 1333mhz to 1866, this why i bought this memory. but when i set xmp the computer just throws a blue rquest up saying pc unstable load optimized defqults or enter bios, can anybody help please? my motherboard is a gigabyte gaming sli 990x chip set