Tripping over trip points

Constantly having problems on two AMDx2-based systems, used mostly for number crunching (one
AMDx2 6000, another AMDx2 5000). The systems go into emergency shutdown anytime two CPU-bound
processes run simultaneously. The critical temp shown by acpi is 60C, (the only) active trip
point is at 50C. If that would be possible I would rather have fan start at lower temp and
throttle CPU when it climbs close to critical.