7950 Vapor-X - HWiNFO64 and GPU-Z report different VDDC

[lehtv]

Hi, I need some help from experienced GPU overclockers. I've got a Sapphire 7950 Vapor-X OC with Boost.

I'm not entirely sure which program to trust. They differ on the VDDC but report everything else identically. I'm overclocking with Sapphire TriXX.

850MHz power limit 0

1030MHz power limit +17

As you can see, both programs report a change in VDDC when increasing power limit.

And another thing. I can't get the card long-term Heaven-stable beyond 1030MHz even at the highest power limit. It won't immediately crash until at around 1150MHz, and below that it will stay stable for some time, then show artifacts and finally crash if left running. But this suggests to me that with only a bit more voltage, I could get rid of the artifacting.

I'm wondering if there's anything I can do. I can't manually overvolt without forcing constant voltage which I don't want to do. The voltage is dictated by the power limit. Should I try a different BIOS? Like a 7970 Vapor-X or a different 7950?

I'm not sure if the card would handle more voltage despite the temperatures being fine. At 1030MHz, VRM1 reaches 85C and GPU stays below 60C at 50% fan speed after 2 hours of Heaven.

Other info:

GPU-Z shot
90.6% ASIC quality
TriXX v4.3.0
HWiNFO64 v4.06
TechPowerUp GPU-Z 0.6.6

 

[chimaxi83]

I don't trust the GPU-Z measurements. When I had my DC II 680, HWiNFO64 was pretty accurate compared to what I read off my multimeter. Not only that, but in my experience, GPU-Z sometimes blows some numbers up to crazy proportions. Based on my own experience, I don't bother using it for its voltage reading capabilities.

 

[MrK6]

Software readings in general are not to be trusted (if it's a component death-type situation), if you really want to know, use a multimeter. I tend to check offset whenever I get a new card.

That said, programs like Afterburner are widely used and the QA on them is top notch. Since Sapphire has its name behind Trixx, I'd assume the same. From here, it looks like you're hitting the wall as far as stock voltage goes. Time to boost it if you want to go further. Also, make sure you keep your vRAM at stock speeds during core overclocking as you don't want to mix in too many variables.

 

[lehtv]

From here, it looks like you're hitting the wall as far as stock voltage goes. Time to boost it if you want to go further. Also, make sure you keep your vRAM at stock speeds during core overclocking as you don't want to mix in too many variables.

As I said, the software readings of VDDC change according to power limit. So the card seems to be automatically adjusting voltage depending on power limit. Is there anything I could do to unlock manual voltage control without forcing constant voltage?

 

[MrK6]

As I said, the software readings of VDDC change according to power limit. So the card seems to be automatically adjusting voltage depending on power limit. Is there anything I could do to unlock manual voltage control without forcing constant voltage?

Is your 7950 a "boost" version or is it just a regular card? If it's a regular card, you should be able to overclock with voltage adjustments without breaking PowerPlay (which downclocks and down volts your card on idle). This isn't to say that you can't do this on a boost version, I just have zero experience with them. That said, I know MSI Afterburner does this just fine, as it adjusts the voltage for the 3D profile only. If this isn't what you're talking about, please elaborate because I'm not sure of the question.

 

[lehtv]

It's a 7950 Vapor-X OC with Boost, a dual BIOS card. The basic BIOS is 850MHz, while the boost BIOS OC's to 950MHz provided the card gets enough power. It can't maintain the boost clock without increasing the power limit.

The voltage slider's value in Afterburner and TRIXX is by default set to 950mV which is what HWiNFO reports when the card is at idle. This could be just coincidental. Afterburner reports 0.806V at idle which roughly what GPU-Z says.

As for load voltage, it seems to be locked to whatever the power limit dictates, and this voltage is reported differently by different programs.

According to HWiNFO64, 1.106V at power limit 0, 1.188V at +17.
According to GPU-Z, it's around 0.922V and 0.982V, respectively.
According to Afterburner, 0.962V and 1.050V, respectively.

Is HWiNFO64 more trustworthy than Afterburner? I should think not since Afterburner is supposed to be used to control voltages.

Adjusting voltage in Afterburner or TRIXX has no effect on reported idle nor load voltages.

 

[lehtv]

If I force a constant voltage slightly higher than what reported by Afterburner at maximum power limit (1.050V), with the power limit set to maximum, this is what happens:

Afterburner set to constant 1.062V

Idle: GPU-Z reports voltage higher than at load, around 1.037V.
HWiNFO64 reports 0.950V, no change there.

Load: GPU-Z reports reports 0.990V, slightly higher than without forced voltage.
HWiNFO64 reports 1.188V, same as without forced voltage.

Afterburner set to constant 1.075V

Idle: GPU-Z reports voltage higher than above, around 1.049V.
HWiNFO64 reports 0.950V, again no change.

Load: GPU-Z reports reports 1.004V, again slightly higher.
HWiNFO64 still reports 1.188V.

I'm inclined to believe HWiNFO64 is making up the voltage because it doesn't respond to changes in constant voltage beyond what the maximum power limit sets. And since GPU-Z reports a different idle and load voltage, it's probably also bogus.

But how am I supposed to believe Afterburner if no third party program will report what Afterburner reports? Opening TRIXX after setting constant voltage in Afterburner, TRIXX will report the same voltage as Afterburner. But that's just the slider, not an actual voltage sensor.

 

[lehtv]

Good news. Installed the Sapphire 7950 OC Dual-X BIOS. Now voltage is fully unlocked (up to 1.3V in Afterburner) with idle power saving and the power limit doesn't dictate voltage according to GPU-Z.

I'll return to overclocking it again tomorrow (getting 5AM here, jesus...)

 

[MrK6]

Good news. Installed the Sapphire 7950 OC Dual-X BIOS. Now voltage is fully unlocked (up to 1.3V in Afterburner) with idle power saving and the power limit doesn't dictate voltage according to GPU-Z.

I'll return to overclocking it again tomorrow (getting 5AM here, jesus...)

Glad to hear you got it working. :thumbsup:

 

[lehtv]

Unfortunately, the Dual-X BIOS increases VRM temps by nearly 10C compared to the stock bios at the same voltages, as reported by GPU-Z and Afterburner. I think I'll just stick with the stock BIOS and not overclock at all until the games demand it.

 

[MrK6]

Unfortunately, the Dual-X BIOS increases VRM temps by nearly 10C compared to the stock bios at the same voltages, as reported by GPU-Z and Afterburner. I think I'll just stick with the stock BIOS and not overclock at all until the games demand it.

Probably because you're actually giving the card some volts. Your VRM temps are fine as long as they're under 110C.

 

[lehtv]

Probably because you're actually giving the card some volts.

I don't think I'm giving it any more volts. Using the regular BIOS, Afterburner reports 0.962V and GPU-Z reports 0.922V or so at power limit 0. Setting the voltage to 0.962V in the Dual-X OC bios, GPU-Z reports 0.922V as before. If I set the voltage any lower than 0.962V, the card will crash at the stock 850MHz. Yet at 0.962V, the Dual-X OC BIOS results in 10C higher VRM temps.

 

[MrK6]

I don't think I'm giving it any more volts. Using the regular BIOS, Afterburner reports 0.962V and GPU-Z reports 0.922V or so at power limit 0. Setting the voltage to 0.962V in the Dual-X OC bios, GPU-Z reports 0.922V as before. If I set the voltage any lower than 0.962V, the card will crash at the stock 850MHz. Yet at 0.962V, the Dual-X OC BIOS results in 10C higher VRM temps.

If you've already determined the software to be inaccurate at best, why continue to put a lot of faith in it? VRM's are simple - if the temps increase and you haven't changed the cooling significantly (assuming ambients, airflow, etc. are relatively constant), then what changed is you probably have more current going through them. The indirect way to test this would be to see if your overclock headroom increased, although the previous "boost" function somewhat clouds this.

 

[lehtv]

I forgot to check the currents. HWiNFO64 displays the VDDC currents along with temperatures and voltages, they were probably higher than with the regular BIOS.

The indirect way to test this would be to see if your overclock headroom increased, although the previous "boost" function somewhat clouds this.

I tried briefly to make the card stable beyond 1100MHz with more than 1050mV, to no avail. And because of near 100C VDDC at that point, I didn't pursue that...