OVERCLOCKING HD3850 HELP PLEASe

I got a hd 3850 by visiontek

when not running any 3d apps i run at about52 degrees, and 0 precent gpu usage.

when playing sin episodes emergence i got 71-87 (average 75 ish) degrees, and 39% gpu activity.

my clock speeds are currently 669/829 ( factory speeds)

how safe am i to overclock it?? i havent yet.

heres my question

i have enabled "ATI overdrive", but have not changed the speeds manually nor have i clicked on " AUTO-TUNE".

will ati oerdriv eautomatically speed up my gpu clock or sdo i have to click on "auto-tune" first.

also, is it possible that by clicking auto tune and using ati overdrive, my gpu gets messed up, without me overclocking manually. overdriv eis supposed to do it safely.

what are the factors that effect video card failure or artifacts?? i know one is temperature. what else??

in other words, if i see that i have a good temperature, can i keep cranking it up?? o is there soomething else to worry about other than temperature??

what is a good temperature for both running 3d aplications and just doiung nothing?

are my temperatures good/safe? thanks alot for any advic eor help! im new to overclocking!!

I would´nt auto tune the card, try set the clock up by 10mhz per cycle and run 3Dmark06, when artifacts start u lower the clock by 20mhz...

My powercolor HD3850card run stable at core-730mhz mem-1000mhz.. I was able to increse my perform in 3Dmark06 by800pts by clocking gpu and mem. (9393pts)

Edit:Hm, i forgot the part about temp. Most new cards can work perfect in core temp up to85-90 celcius. more inportant is that mem in the 3850 cant handle the heat, and thats the only reason u cant go further to corespeed 770mhz.

(the cooler is a copper cooler and higer corespeedwill heat mem up.)