If it's the Pentium D 805, then the maximum temperature for it to overheat is set to 64.1 deg.C as specified from the intel site: http://processorfinder.intel.com/details.aspx?sSpec=SL8ZH . However the most precise value for the processor temperature would be found in the BIOS rather than using 3rd party software on the operating system, since all these software take the values from the BIOS itself. Also temperature monitoring is always down to the motherboard. Check with your motherboard manufacturer for any bios fixes and make sure your system is well ventilated and you are always using compatible components in your system. Check that the cpu is well seated in the socket as well as the heatsink. Your cpu running at 133-158, i think is too much,as it's almost twice the themal specifiations.
At this temperature, I guessed the motherboard should be automatically shut down the system.
I am thinking that the monitoring software that you are using is misreporting the temperature.
You can check the temperature of the CPU in the BIOS itself.
Actually if your system is reporting high temperature under high workload, you will need to check for motherboard manufacturer. All temperature reporting is down to the motherboard mainly.
It can be due to any of these:
a) bad integration
b) PSU not ATXv2.2
c) Chassis is not TAC (Thermally Advantage Chassis)
d) BIOS Issues.
e) Monitoring Software
Make sure that you are reading the temperature from the BIOS itself.
Intel Monitoring Software for Intel Motherboard only:
Where to check your max CPU temperature:
Get the SL number of your CPU.
Check on these website below:
If the temperature is still high in the bios, try the system out of the chassis.
Re-integrate the CPU with new clean thermal paste. (small amount pea-sized)
Update the BIOS and see the difference.
Check with the BOARD MANUFACTURER.
Let me know how it goes.
The temp I stated was Fahrenheit not Celsius. 64.1C (per. the spec. you quoted) is 147.3F so my cpu is close to right on the money except for the spikes and they may not be real. But the spec. give only one temp. 64.1. isn't there a range of normal operating, surly they don't expect the cpu to stay at 64.1 100% of the time.
As i said earlier in my above post, if you can get your SL number of the CPU, you can check it on the website that I gave you.
Usually, the pentium family has a high temperature operating range. It is worth of doing the tests that I had advised you to do and then let us know how it goes. The temperature that you told me seems to be alright for Pentium, but again check on the website I gave.
I gave you all the reasons why a system can overheat, so try to eliminate one by one.