I5 - 2400 (sandy bridge) - high BIOS temp?

I just finished installing my i5 - 2400 + BIOSTAR M67 MU3 m/b. I've installed PC's before but never worked with the sandy bridge CPU's. After applying some Artic Silver 5 to the 'stock Intel heatsink' I went the BIOS and checked the CPU temp and it was high for a BIOS reading.

When I boot into the BIOS the CPU temp starts off around 45C and then rises to about 52-53C. Is this normal in the BIOS? (I've read that the sandy bridge BIOS temps are high).

I've reseated the heatsink 3 different times (only a 2-3C change), cleaning off the heatsink/CPU with Artic Clean 1 & 2 each time, then applying a dab of AS5 to the center of the CPU. I'm confident I've done everything correctly but I just want to make sure this is normal. I haven't installed any OS yet.