Recently purchased 4 gb. stick Patriot DDR3, 1600MHz, CL11, 1.5V. My motherboard is Gigabyte GA-P55M-UD4 and supports dual channel memory, has 4 slots and i have alredy 2 x 2 gb sticks installed (Super Talent), which are 1333 MHZ. Read it won't be a problem. When I tried to instal the new RAM yesterday, both times BIOS signalled for problem with the ram. Tried the two different free slots. I don't know if the system boots, because I panicked and pulled the plug right after the BIOS started beeping. Do i need to adjust the settings in BIOS or something? Or it's just compability problem or the RAM is faulty?