Do you run stock clocks on those 5410's? The lower the clock, the higher the stable temp threshold.. mine crash at 3,2Ghz when they hit 80C real/90C Everest.. I tried without fan just to see, lol
Oh and in my rig, everything gets rather hot.. NB, Rams, even the Heatpipes from the HR-01's. But temps are ok even at 30C ambient, plus this system is a rock at FSB 430