SIGH! I had 8 - 1GB RAM sticks spread out between the two riser cards in my Mac Pro. About six months ago I turned on my Mac Pro the and the power light began blinking white. I narrowed it down to slots 3 and 4 were bad on my lower riser card. That knocked me down to 6GB of RAM. About one week ago I turned my Mac Pro on again and the white light started blinking again!!! Slots 3 and 4 on the upper riser card went bad this time. Now I am down to 4GB of RAM. My Mac Pro is a 2008 [early] btw unless you saw it in my sig already. I am just curious if this is common for a 2yr old Mac Pro for the riser cards to go bad like this. When I get a spare $200 I plan on replacing both riser cards as I have not found them anywhere online cheaper than about $100.