dolmaface

i overclocked my cpu, and now i want to overclock my 8600 gts. I did some research on it finding for the 8600 in particular 40 C is cool, 50- 60 C is normal, and 70- 80 C is Hot. For some reason though when i overclock the card, even to 800 mhz, the temperatures stay the same. i checked on nvidia monitor and gpu- Z. Same results from both. I'm using and antec 900, case fans all on high, and gpu fan on about 60 percent. Is this normal, safe?