HD 4850 overclocking problem HELP NEEDED!

i am having problems overclocking my 4850, it the palit 4850 http://www.palit.biz/main/vgapro.php?id=853
i can only overclock it from 625mhz to 635 and memory clock speed from 1986 to 2082 isint there away that i can overclock it higher. the tempreatures are stable idle at 34C and at full load only 58C.

here is my computer spec
antec nine hundred case
e7200 cpu 2.5ghz overclocked to 3.75ghz
4gb ddr2 overclocked at 920mhz geal edtion
asus p5q l pro p43 chipset motherboard
antect earthwatts powersupply 500 watts (good expensive quality powersupply bought for £65 thats about $80 to $100

so can anyone help me out

help!!!

are you saying you cant overclock it higher or that its just not stable past that level?

Thats probably the farthest you can go then.

I like your Kazama avatar. Lol. Tekkennnn. But yeah, or it could definitely be your chip. Sometimes people get duds. None of em are ever QUITE the same. Some are better, some are worse. Have you done a fresh reinstall of drivers? And what utility are you using to overclock your 4850?

Fan at max, then try again, try to use different programs to oc

i have tried using riva tuner and ati tool but i start o get aritfacts whenhitting above 645mhz
do you think i need a new card.

i got my fan running full it still gets about the same results

Its most likely the board, 4850's are normally built on the more unstable 4870 boards unless it comes factory OC, atm mines stable on 750 1150.

You can't get a new card for you not being able to overclock more...
The card probably can't go higher