I have the exact MB and have the same problem with temp readings, it is the motherboard, I am running a barton 2500, before I updated my bios the readings of my CPU temp floated around 105-125F, since I flashed it, it runs at 130-150F, so I figure it is the motherboard and not the CPU. However the motherboard temps stayed the same when I flashed, which was at about 95-105 in a Lanboy case, I have since switched to an antec 4U server case and it now reads 84-89 degrees, so yes the case makes a huge difference. Anyway, I hope this helps, if you have any questions fire away!