How long should i scan for artifacts?

two questions

1) the title

2) when its scanning for artifacts. why does the temps go up really fast a;thought the speeds are the same??

I usually just run it for a couple of mins at most and then try and game with my settings. I usually do this because the artifact scanner seems to be a little more sensitive and it'll say you are artifacting and when you run a game the game runs perfect and artifact free for hrs. on end. Also the temps are rising because the card is being used.

what would be a safe range of temps in full load??

yea ATI tool is very very stressful and picky about finding artifacts...I go by game performance just like Nexus, if it doesnt artifact in game then I consider it stable.