CPU Temperature (Phenom II 720)

My CPU at idle starts from 29 degrees to 35 degrees. In times of load i think it can go all the way up to 50 degrees celcius. I have put this processor in a HTPC computer, unfortunately it does not have any side vents, but it has all acrylic plastic windows instead. Opinion based, is 50 degrees safe for my processor to be running at load? This is running all three cores at 100 per cent with ram at 95 per cent. Will it last me for a rather long time and i don't have to worry much about it? I have put in all the cooling appliances that i can, no more space for any more fans. Should i just take the sides and top panel of the computer and let it cool sufficiently, or should i not bother?

73 degrees is maximum i thought, looking at the AMD website. Realy, anything above 50 degrees is bad? So my cpu is ok since it was overclocked to 3.2ghz and that was a stress test to 100 per cent for sometime.

yeah, you know what, i turned the 120mm fan the other way round so that it is blowing air into the case. The processor says it is at 23 degrees now which is 1 degress above my room temperature, and at load it goes up to no more than 33.5 degrees. This is smashing. Plus this is in a small cube case. But cooling performance isn't sacrificed, i also have a PCI fan, the evercool guided missile which works very well exhausting all the air out of the computer at the back.