on paper it should helps but that all depends on how cool is the card and how good the core can overclock.

basically luck will also come into play.

increasing voltage will make the signal much stronger thus it will help if ur increasing clock frequency. but increasing clock frequency only, wont burn ur GPU, but increasing voltage will definitely increase the temperature thus it might burn ur GPU if u don't keep the temperature under control....

there r few options:

a) tune the bios & reflash
b) if ATI card, use ATT (ati tray tools), but doesn't support voltage tuning on 5k series.
c) use s/w provided by manufacturer, such as MSI Afterburner (only works with specific gc by dat manufacture, however, lets say u own a Sapphire 5850 instead, u could flash the bios to MSI 5850 & use afterburner)

actually flashing ain't dat risky if u know how to recover from bad flash.
for nvidia, u could do a "blind flash" recovery (google the steps).

i suggest try ASUS or EVGA bios since they usually provide the most overclock ability gc.

http://www.techpowerup.com/vgabios/index.p...face=&memSize=0

try EVGA bios.

http://www.techpowerup.com/downloads/1762/...sh_5.91.01.html

& dis is NVflash, usse to flash ur nvidia gc bios.
all u need is create a bootable pendive, put dis file in ur pendrive, & set ur mobo 1st bootable to USB. (if no useb bootable, u'll hav to create bootable cd o floppy)

steps:
1) backup ur current bios & put it in the bootable pendive (rename it to something ex to remembe such as "old.rom").
2) dl ur new bios & also put it in the bootable pendrive (rename it to something ex to remembe such as "new.rom").
3) boot the from the pendrive & following r the commands.
4) if flash successful, reboot & try oc ur card again. (suggest u plug out the pendrive & dun chance the 1st boot device setting yet, coz later might hav to blind flash)
5) if flash fail o not compatible (no display), dun panic, ur pc actually still boot, wat u hav 2 do is blind flash. wait manbe half a minute, assume dat it edi boot the pendrive (just dat u cant see display), & den use force flash but dis time flash bck to ur ori bios.