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I'm now on my 2nd Vapor-X 7970 Ghz. Both of them have had hard, low clock ceilings on the core. The first one topped out at 1150Mhz, the replacement topped out at 1175Mhz. The weird thing is, adding voltage did absolutely NOTHING to the OC ceiling/head-room. The first card would reach 1150Mhz completely stable on stock voltage (1.256v) with no problem, but no amount of voltage increase gave any stability increase beyond 1150Mhz. I maxed out the Trixx voltage slider up to 1.381v and I still could not get my clocks to budge even slightly past 1150Mhz, which they achieved at 0.125v LESS!! Second card behaves exactly the same way. GPU-Z sensors actually do read higher voltages, but the core temperature essentially remains exactly the same regardless of the amount of voltage being read in Trixx and GPU-Z, and 0.125v usually causes quite a noticeable change in temperature. Something seems really strange here, as if these particular cards have some sort of voltage limit on a hardware level even though many software applications do allow you to adjust a voltage slider. Both have awful ASIC scores btw, (the first being 63.4, the second behing 56.3) in case that might have anything to do with it.

Does anyone here have a DIFFERENT experience with a 7970 Vapor-X?
 

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I'm having the same issues. I can get about 1120MHz stock and upping voltage does nothing. I'm currently using Trixx v4.6.0. But looking at GPU-Z on my voltage meters I'm getting some crazy vdroop so that could be a problem... Example at 1300 VDDC
Load
Idle
My card also has a ASIC score of 57.5
 

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I suppose you could try the modded Trixx 4.4 beta which has a higher voltage headroom.

Although shouldn't you be happy with 1150mhz ? I am, I don't have a high headroom either. But then my card is fine with just 1.175v for 1150mhz.

ASIC Quality is 77.2% here ( Dual-X non-ghz) , perhaps your card is suffering from voltage leakage due to the low ASIC Quality.. I don't know.
 

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Quote:
Originally Posted by iamhollywood5 View Post

I'm now on my 2nd Vapor-X 7970 Ghz. Both of them have had hard, low clock ceilings on the core. The first one topped out at 1150Mhz, the replacement topped out at 1175Mhz. The weird thing is, adding voltage did absolutely NOTHING to the OC ceiling/head-room.
Which means your voltage adjustments most likely have no effect. Did you monitor the voltages in GPU-Z under load to check if the voltage indeed changes?
Try switching to the other BIOS with the button on the edge of your card's PCB. One of the two BIOSes should allow voltage control.
 

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Discussion Starter · #5 ·
^ In the OP I stated that GPU-Z sensors do read higher voltages. It's just strange that the temperatures don't increase with such a big voltage increase.
Quote:
I suppose you could try the modded Trixx 4.4 beta which has a higher voltage headroom.

Although shouldn't you be happy with 1150mhz ? I am, I don't have a high headroom either. But then my card is fine with just 1.175v for 1150mhz.

ASIC Quality is 77.2% here ( Dual-X non-ghz) , perhaps your card is suffering from voltage leakage due to the low ASIC Quality.. I don't know.
I've been using both the modded 4.4b and the official 4.6, and the 4.4b maxes out at 1.381v, which I tried and saw no difference in clocks or temps. 4.6 maxes out at 1.3v but has the Force Constant Voltage option (which really doesn't do anything at all). I would be happy with 1150-1175 if this were a basic HD 7970 (non-Ghz Edition, no premium cooling or custom PCB) but I shelled out the extra $80 for the Vapor-x GHz edition because it was one of the higher-end 7970s from Sapphire and it should have a higher ASIC quality and better chance at a 1200+ overclock. I was hoping 1250 to 1300, but now that I'm on my second card it's just not meant to be. Just hoping after a year I can get some ebay money out of it and upgrade to the best of the next generation of cards from AMD or Nvidia.

And you're right about the card likely having a lot of voltage leak, that makes sense and I wouldn't be at all surprised. I'm assuming voltage leak also only gets worse as you try to increase it, and 1.3v+ is a really high range for 7970s.
Quote:
I'm having the same issues. I can get about 1120MHz stock and upping voltage does nothing. I'm currently using Trixx v4.6.0. But looking at GPU-Z on my voltage meters I'm getting some crazy vdroop so that could be a problem... Example at 1300 VDDC
Almost all 7970s have a crazy Vdroop problem. AMD did it intentionally, it's something called Load-Line Calibration and it's programmed into your cards BIOS. So far nobody has figured out how to edit the BIOS of these cards to change or disable LLC. ASUS GPU Tweak is the only software I know of that can let you mess with LLC but pretty sure it only works with an ASUS BIOS. Trixx 4.6 has "Force Constant Voltage" which was intended to combat LLC but it really doesn't to ANYTHING to reduce Vdroop, all it does is keep maximum voltage when you are idling instead of allowing it to drop to 0.85v.
 
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