What are normal temps for an AMD 3.1Ghz "Callisto" Dual-Core w/ all four cores unlocked?

I have an AMD 3.1Ghz "Callisto" Dual-Core w/ all four cores unlocked running in my system right now. For the heatsink/fan I'm using an Asus Triton 77 and MX-2 for thermal paste. The temperature display on my motherboard is reading about 40 degrees at the moment, but when running games it'll hit 50 degrees. Is that a "normal" or safe operating temp?