Hi There, What is the best way to test RAM? A few months ago I installed 2 x 2GB Samsung modules from OWC in my 24" iMac and upgraded to Snow Leopard. Since then, I have received a kernel panic, my computer has shut down unexpectedly, and it has been randomly freezing up, along with blinking pixels appearing and horizontal lines appearing across the screen on my desktop and in Safari. Any suggestions would be greatly appreciated. Thanks!