You might try this. Pull the heatsinks off the processors and clean ALL the thermal compund off the processors and heatsinks with some rubbing alcohol. After doing this apply a small amount of thermal paste, I recommend Arctic Silver, to each processor and replace the heatsink. Apple uses entirely too much compound and this oozes out to the surround area and may cause the smell you are all experiencing. I have a 2.66 quad core mac pro and I have never experienced this smell. Hope this helps!