Does anyone have experience with these 2 CPU's I am running about 35C on water and 40C on a Zalman 9500 with my E6400.  This is measuring it with a Coolermaster Cooldrive 4 temp probe and a temp probe on their watercooling unit at stock.
 
A friend of mine has an E6700 and is getting low 30's with a Zalman. What gives?
 
This is a new build so pay NO attention the the rig below
 
Thanks

Try resetting the water block. It may have poor contact with the cpu or too little or too much thermal paste.

Are you overclokcing? Overclocking produces more heat.
 
If not,  it sounds like your thermal barrier. Are you both using the same thermal paste?
 
Did you know that for a new install with thermal paste your temps will start out high and go down after a couple of weeks as the paste stabilises?
 
how did you install the paste? Thick layers are much worse than slight smear. Also, see the Arctic Silver website for a good description on how to do it right for C2D.

E6600 have 2MB more L2 cache. It's run ~2-5C hotter.  
Notice that different motherboard reads different temperature.

That seems logical to me and was how I thought it should behave.  
 
This is an Asus P5WDG2-WS PRO board I just read that it may be overvolted so I will crank it down and see what happens