Varied Core Temps: What's Normal?

Hi Guys,
I've been prepping to overclock a new, lapped Q6600 and have collected some stock setting benchmarks. I'm noticing quite a bit of difference in the temps of each core:

Idle Temps:
SpeedFan: 26, 32, 23, 27 C
CoreTemp: 27, 32, 23, 27 C

Load Temps:
SpeedFan: 49, 49, 44, 45
CoreTemp: 49, 49, 44, 45

At idle, core 2 is running between 5 - 9 C degrees hotter. They seem to be closer at load (~ 4-5 C difference). Is this anything to worry about? Is it normal to see one core running hotter?

I have a P5K Deluxe mobo and a Xigamtek 120 fan/heatsink.

Thanks.