5870 vappor-x 1gb problem on OCING

[joyyen]

hi guys i am from malaysia

i have bought a 2nd hand sapphire 5870 vapor-x 1gb factory OC version and i tried to overclock using RBE flash in DOS mode

now i have face some problem no matter how i overclock or underclock the GC the GUIMINER just showing 255+ MHZ mining speed only !

i have my own mining farm and i have bought many cards all of them have no problem on OC them !

but i cant OC this 5870 Vapor-x Factory OC edition !

any help here ?