I just installed the temp senors on the NB and SB and did some tests
I have added a 120mm fan onto the outside of my case that is centered over my Video card and the NB there are vent holes on this side panel so the air flows in there good I also have a
ZALMAN ZM-NB47J Aluminum Heatsink on the SB that cooled it down considerably
NF = side fan off
WF = side fan on
stock 533/1066 2133 MHz 4-4-4-12 2 T
vcore 1.25
vdimm 1.92
NB 1.2
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case fans 2 120mm fans @ 1300 rpms
cpu fan @ 980 rpms
NF
SB 31c
NB 49c
WF
SB 27c
NB 35c
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OverClocked to 3400MHz
850/1700 3400MHZ 5-5-5-12 2T
vcore 1.325
vdimm 2.08
NB 1.39
case fans 2 120mm fans @ 1300 rpms
cpu fan @ 980 rpms
NF
SB 32c
NB 58c and climing I turned the side fan on I didn't want to lock up
WF
SB 29c
NB 44c steady, while benchmarking
case fans 2 120mm fans @ 1700 rpms 100%
cpu fan @ 2400 rpms 100%
running 3Dmark 06
WF
SB 29c
NB 41c steady, while benchmarking
cpu 39c
core1 36c
core2 32c
MB 34c
HD 32c
Video Card 67c
I would say an extra fan blowing on the NB is defiantly needed, if your overclocked.