I had the same problem, except that the temps were really high (60C).
I purchased a couple of temp/fan controllers (Logysis and AeroCool) that had temp probes. After installing these in 2 different Rigs and placing the probes so that they contacted the edges of the CPU and GPU my temp readings were much more reasonable.
The Logysis costs about US$20 and can monitor 3 temps and control 3 fans.
Or, you could borrow a Fluke temp reader and verify that way.
[SIZE=\"1\"]E6400 @ 3.4 , Noctua 120
7900GT @ 670/1680 , VF900
2 x 1GB Patriot 6400 @ 425
WD SATA 250GB
Neo HE 550
P180 / G15 / MX1000[/SIZE]