So it's your case ambient or your TI4600 that's reaching 55oC? If it's the TI4600, that's actually quite normal, and in fact very reasonable! If it's your case temp I'd wager that you're reading the wrong value, or your monitoring hardware's farked. I've built XP2200+ systems in tiny, unventilated cases (just the PSU fan) and never seen case temps that high. Do you live in the desert or some warm climate? If so, there's not a lot you can do outside of air conditioning!
I find that a lot of people spend excessive amounts of grief on temperatures of this and that. If your computer's working fine and your CPU temperatures are OK just turn off the monitoring system and use the damned computer instead of coddling it and worrying about every degree Just my 0.02.