[Solved] Overclocking gpu

i am new to overclocking i was given a suggestion to use al suite 11 over afterburner. i looked through al suitell and i only saw places to overclock your cpu
i went to amd vision engine control centre
under performance and choose graphic overdrive
it allows gpu clock settings to 850 mhz
and memory clock to 1200 mhz
i did not take the memory above 1140

how do you up the voltage i read a test were the said with voltages like
1.22volts they reached between 940-950 mhz they called that the sweet spot stable with a memory of
1150 mhz

any suggestions were i can watch some videos you tube all seem to use afterburner

my system is
ASUS M5A99X Evo
AMD Phenom II X4 965 Black
XFX Radeon HD 6850 Fansink 775MHZ 1GB
Western Digital Caviar Black 500 gb
Corsair TX750
G.SKILL Ripjaws X F3-12800CL9D-8GBXL 8GB 2X4GB
Zalman Z9 Plus

i am just looking for places to do more research i have tried searching
al suite 11 with explorer firefox on you tube
any other suggestions

i noticed when i ran pc mark7 and furmark 1.9.2 it ran a lot smoother after i made these changes
i would like to get the gpu to what they call the sweet spot

catalyst control center does'ny allow voltage change. u can use sapphire trixx or msi afterburner or flash the bios to a 6850 with higher voltage but i suggest get as high as u can without adding voltage because it makes the memory hot to and you get lower on that. the memory clock is more limiting on this card. i use mine at 850/1172 it's a sapphire 6850 hd.

Best answer selected by geo22.