I have also have a Core™ i7 930, and two of my cores (Core #1 and #3 just, like yours) are always higher than the rest. The difference between mine is similar, ranging from 3°C - 5°C. I wouldn't worry about it too much.
 

jsrudd

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Jan 16, 2009
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I had one core that was a little hotter (about 3 degrees). I then, like you, reapplied the thermal paste and remounted the cooler. It was still hotter and I've found that its pretty common for cores to be different temperatures. One of the differences between the different i7s is where they were sourced from. When a processor is fabricated a large circle is made and then the processors are cut from the larger circle. The closer to the center the less variation and those chips go for more. The farther away, more variation and so you get the 920s.