I've got 8x Micron 4GB DDR2 FB-DIMM 800 MHz sticks since January 2010. In April 2011 one of modules failed. I've replaced it with Hynix module. Today another one failed. Why is this happening ? Poor cooling ? I use sticks with small heatsinks, but I've added a small Zalman heatsink on a core of each module to keep them a little bit more cooler. I'm replacing the broken module with Kingston module.