~55C seems to be the max full load temp with the Phenom II CPUs for 100% stability. While the chip itself can safely be run to 60C or more, it *can* experience errors above ~55C under full load based on a lot of user feedback. That doesn't mean that your CPU will experience errors above 55c, it just means that it *could* as many other folks have observed.
Idle temps of 34C-36c would be completely normal. In reality the only temp that actually matters is the full load temp. There are many factors that impact CPU/GPU temps in addition to load and frequency so as long as your processor operates within the max temp under full load, you're good to go.
Building a reliable PC involves more than just assembling the parts. You need to be able to configure all of the BIOS settings appropriately. This can be quite involved and frustrating as it can require a lot of trial and error with stress testing. It is however often the only means to get a 100% reliable PC.