X800 overclocking itself?

I've got an X800 pro non-vivo, and it's been working marvelously, and oc's very high. I'm running it at stock, since no games really require it any faster, and have had no problems up until the other day when i turned my computer on, and atitool told me the core was at 506....now, the default in atitool says 475, but for some reason, whenever i start it, it's at 506, memory stays at 450..anyone have any ideas as to what might be causing this? If i click "default" in atitool, it resets it, but after every reboot, it's running at 506core...

my ati tool does that with my x800 card - it always reports random core speed in the general correct speed area, but not usually exact... i wouldnt worry

set up ati tool to load on start up,load default 450/475 profile,its very easy.i like ati to load at start up so i can see my temps anyway.i also load at
500/500 and let it warm up a little, then crank it up from there. only for games though.