When I overclocked my 8gb ddr3 1333mhz ram, when i open it again it show black screen but after 20mins maybe, it show the windows but it so lag, it hard to move the crosser of the mouse, then i try to check the task manager, it show that my ram was only 300mb and that cause the black screen in startup and the lag. Do i need to replace the ram? Or there is a solution for this? Please help me, i need my computer for my school works.