i have been using my mac pro quad core xeon 2.66 for several years with only 1 stick of ram (16gb) i have never had any lagging or performance issues until recently. could this present any problems, slow hanging or corruption? i started having weird graphics issues several weeks ago and my system has been slow, especially running firefox. i just wanted to get feedback to see if anyone thinks 1x16 is a poor performace setup or would possibly present any issues. the dimm's on these are DDR3 ECC 1066. i have a second machine i purchased to see what was wrong by process of elimination, but when i changed to 4x2gb from the other machine, it still occurred. i believe the HD was the issue, but just wondered if the ram configuration may also have something to do with it. is 1 x 16 ok? or should that be either 2x16 or 2x8? does it matter?