A few days ago, while I was compiling some stuff on my ALIX.3D3, I discovered a very high CPU temperature by chance:
M/B Temp: +59 C (low = +0 C, high = +70 C) CPU Temp: +71.1 C (low = +0.0 C, high = +70.0 C) ALARM
I downloaded the datasheet of the AMD Geode LX800 CPU to check which temperatures are OK. On page 598 I found that my model (ALXD800EEXJ2VD) is fine for temperatures from 0 °C to 85 °C. Anyway I looked in my spare part box if I could find a suitable heat sink and fortunately I found a 40mm x 40mm x 9mm one. So I ordered some thermal adhesive and installed it.