saphire 4850 - why can't get more than 660 core :( ?

[asd1301]

i see ppl with my card :
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102747
get to 700+ EASY !....
when i get over 660 core my screen goes off in heavy games ....
am i doing something wrong ? if i rais 10 on the core should i raise also 10 in the memory or something ? maby the core and the memory not synchronized ? that's why i can't go to 700 core ?
temp ok i guess ...75 in games on 40% fan by profile ....

http://img366.imageshack.us/img366/7224/sssssssssssssssssssti2.jpg

 

[WJA96]

It's entirely possible you just have a poor clocking card.

[Edit]And claims made by people are very different to seeing it with your own eyes. I have 4 Sapphire cards - 2 HD4850's and 2 HD4870's and none of them are stable at what ATI Tool's automatic overclocking will take them up to.

Isn't it quick enough at stock anyway?[/Edit]

 

[gurusan]

i found these are sensitive to heat. I could only get 690mhz stable on the stock cooler but with watercooling could get to 710mhz stable.

Now I'm at 1.34v and 820mhz stable, temps never go above 33c.

 

[marscay]

some brands also come with higher voltage through bios, my 2 powercolors came with 1.15v 3d under load measured with DMM and i've seen others measured @ 1.10v.....cant remember the brand.

and as gurusan has mentioned cooling the card will help also.

 

[gurusan]

yup, you can try flashing your bios to 1.2v (max you can change through bios). That should put you above the 700mhz mark.