Help!! Visiontek Radeon HD 7970 cannot overclock with 1.3v

[manyee]

Hi guys,

I just received the Visiontek Radeon HD 7970 from the current TigerDirect deal.
It's a very nice card and I'm surprised that the noise is even better than my last XFX Radeon HD 7950 Double D and it cools down better too.

I've been trying to OC the 7970 and the highest I got so far is 1200 core/1600 memory @ 1.237v with customized fan profile using Trixx. It is stable with Heaven test & Kombustor stress test.
Somehow, whenever I up the voltage to 1.296v or 1.3v , the card will crash and give me black screen even though I left the setting still at 1200/1600 (I used Heaven test for this)
Can anyone help how to solve this? How can I OC higher?
Is 1.237v the limit of my card?

Btw, my ASIC reading is 78.7% using GPU-Z and the stock voltage shown on MSI AB & Trixx is 1.112v.
I left the BIOS switch at #1. Is this correct? (as far as I remember, #1 is for OC and #2 is for safety BIOS, right?)

Thanks in advance!

 

[manyee]

This is about as far as the 7xxx cards can hit, some will go to 1300mhz but with water cooling.

For instance, my 480's ASIC is 68.8, which means my card will overclock with higher voltages and hardcore cooling.

This translates to your card being good with lower voltages, but topping out at a max clock or voltage.

I hope i have said this in some sort of understandable way for you.

If i was you, i would go to a custom cooler from here, or seek W/C....
1200 is a very nice clock as is

Thank you for the reply. I can understand your explanation related to ASIC number. The reason I tried to go beyond 1200MHz core is because I saw some reviewers with ref card can go beyond 1200MHz. Maybe that's a cherry pick card .

Btw do you know the answer to my BIOS switch question?