Is my overrclock safe -6950

[jonny512379]

Hi

As the title says, i am wondering if the OC i have put on my sons Sapphire 6950 is safe?

I have the core clock running at 900
The memory clock running at 1400
The GPU voltage is set at 1.200v and i also have the Power Control Settings at +20% (correct me if i am wrong but i think this is a total voltage of 1.420v. I am unsure if this is the voltage at all times or if the +20% is only provided when it is required?)

It is the voltage that i am worried about as i can find no good info on what is a safe voltage for this card.
The GPU temps all seem fine, using a custom fan settings (as the default fan settings seem terrible and too low i feel) the temps stay at no more than 65c in game and under basic benchmark tests.

To get this OC i am using a combination of CCC and TRIxx (from Sapphire) and also loading up MSI Afterburner so that i can see frame rates in game.

I do hope that this OC is safe as it has improved the permanences of this card by over a third according to benchmark testing and has allowed me to set most game graphics to maximum, inc AA and Atmospheric AA and i still get frame rates of 60!. (very impressed with this card!!!)

Also if i up the core clock much over the 900 mark this caused freeze ups, but i dare not increase the voltage to see if this stabilizes things... The memory clock would probably be ok increased too.
(this card is running with its original BIOS as i don't want to do the 6970 flash until i hear a little more about the voltages, etc. or i may just unlock the shaders once i work out how to do this...)

Any advice or opinions are greatly welcomed, so i can sleep at night without fear that the card will "go critical".......

Thanks

 

[drunkenmaster]

power setting has nothing to do with voltage at all, you're running at 1.2v, its completely safe, the voltage itself won't become dangerous at a high temp but I wouldn't continue to run a higher than stock voltage IF your temps were dangerously high, even then you're talking 95C+.

 

[jonny512379]

power setting has nothing to do with voltage at all, you're running at 1.2v, its completely safe, the voltage itself won't become dangerous at a high temp but I wouldn't continue to run a higher than stock voltage IF your temps were dangerously high, even then you're talking 95C+.

Thanks Drunkenmaster, i think i understand a little better now then about the power settings (am i right to assume the power means "current/watts/amps" and not Volts then?).
So if my MAX temps are 65c would this mean i am ok to increase the voltage over the current 1.2v in order to increase both clocks?

 

[tommybhoy]

I wouldn't be to keen to up the memory myself from where you have it, if you go to far it will start throttling and you will lose performance.

I can get 1GHz on the core @ 1.265V with mine with unlocked shaders, on custom cooling with a AC extreme though, so keep an eye on your temps.

 

[scorpionUK]

Thanks Drunkenmaster, i think i understand a little better now then about the power settings (am i right to assume the power means "current/watts/amps" and not Volts then?).
So if my MAX temps are 65c would this mean i am ok to increase the voltage over the current 1.2v in order to increase both clocks?

Power is measured in Watts.
Current is measured in Amps.
Voltage is measured in Volts.

Power = Voltage x Current

Increasing voltage increases power consumption for the same current, which also increases heat output. Increasing voltage can help achieve higher stable clocks, but it may not make any difference. Sounds like you have a bit of head room to try for higher clocks at higher voltages, but there tends to be diminishing returns as you go higher.

 

[Cythx]

Power is measured in Watts.
Current is measured in Amps.
Voltage is measured in Volts.

Watts = Volts x Amps

Increasing voltage increases power consumption for the same current, which also increases heat output. Increasing voltage can help achieve higher stable clocks, but it may not make any difference. Sounds like you have a bit of head room to try for higher clocks at higher voltages, but there tends to be diminishing returns as you go higher.

So does this mean if my GTX 580 uses 300 Watts at 1.025 Volts, it would be using 293 Amps?

 

[scorpionUK]

So does this mean if my GTX 580 uses 300 Watts at 1.025 Volts, it would be using 293 Amps?

Good question. No is the answer, though what the answer is beyond my knowledge of electronics! The formula is correct for a simple Direct Current resistive circuit, but things are actually more complex when using mains Alternating Current and more complex again, I'm guessing, when things get extremely small like in a graphics card chip.

 

[drunkenmaster]

Yes is the answer, remember the power circuitry drops voltage and increases the ampage available, the current top end cards use silly ampage.

The 6990 as a card is capable of producing 740amps of power total with 4 80amp capable phases per core, its MASSIVELY overspecced, which is why the VRM temps are massively down on 69xx cards over any previous 5xxx cards. The 590gtx is dangerously borderline on capable spec as they've used weak ass VRM's on it, iirc its something like 5 phase 40amps per phase on each core so total both cores shouldn't really draw more than around 370W.


Think of it like this, your 1000W psu(the rating doesn't matter that much) is say drawing 400W in an i7/580gtx system, thats only, with 230v, 1.73amps, but your psu can provide up to say 80amps on the 12v rail on a PSU that size. The same step down in voltage and exponential increase in amps used happens on the gpu vrm's aswell.

 

[belial8321]

I assume you did overclock with CCC? if so im pretty sure theres nothing bad you can really do to your card with this software

 

[jonny512379]

I assume you did overclock with CCC? if so im pretty sure theres nothing bad you can really do to your card with this software

Thanks all

I did the main OC with TRIxx from Sapphire as CCC would not let me up the clocks past 840 and 1250, nor up the voltage.
At present i am using both CCC and TRIxx to get this OC.
I have the clocks and fans set in TRIxx;
And the Power Control set in CCC
(it is a pitty that they do not all offer the same features, also TRIxx does not seem to hold the clock settings after a reboot, i have to set them evey time i reboot ).
Both of these programs are recommended by the manufacturer (Sapphire) so i am hoping you are right in that they can not cause damage.

I don't like the idea of flashing the BIOS to the 6970, but would people here think i will see an improvement by unlocking the shaders, as the card is already performing very will with all games i can throw at it and i would not like to reduce this......

Although the wattage is 250W, i would think the fan uses up most if this, or at least a good amount or am i wrong again? but 200+ amps sounds allot for a PCB to handle.

Thanks again...

 

[xsistor]

So does this mean if my GTX 580 uses 300 Watts at 1.025 Volts, it would be using 293 Amps?

No because the 1.025v refers to the voltage fed to the IC and 300w would refer to the total power of the entire system (and by system I mean GPU). There will be power dissipated in other ways across the entire PCB, including power lost in various ways (joule heating for example. Radiation as another -- At high enough frequency everything eventually behaves like an antenna and radiates all its energy into space.)

Good question. No is the answer, though what the answer is beyond my knowledge of electronics! The formula is correct for a simple Direct Current resistive circuit, but things are actually more complex when using mains Alternating Current and more complex again, I'm guessing, when things get extremely small like in a graphics card chip.

That's actually quite correct. P=VI is still correct and usable (to some extent. eventually everything boils down to Maxwell's Equations), but V and I may no longer be real variables, and may instead be complex variables or pure imaginary variables so the situation becomes more complex (pun intended ) .

While the supply voltage itself will be DC as it is converted to DC by the PSU, the actual circuits will use power in very complex ways, creating various oscillations and such. It is hard to say precisely what the power would look like without analysing it. And often that means simulating it because it is not easy to analyse an analogue electronic circuit. There are no general solutions to them. But capacitive and inductive effects on the board will cause the power to behave in complicated ways. But again, any modern powersupply in practical use will have some form of active power factor correction which will make the load appear as purely 'resistive' as possible.

 

[belial8321]

Thanks all

I did the main OC with TRIxx from Sapphire as CCC would not let me up the clocks past 840 and 1250, nor up the voltage.
At present i am using both CCC and TRIxx to get this OC.
I have the clocks and fans set in TRIxx;
And the Power Control set in CCC
(it is a pitty that they do not all offer the same features, also TRIxx does not seem to hold the clock settings after a reboot, i have to set them evey time i reboot ).
Both of these programs are recommended by the manufacturer (Sapphire) so i am hoping you are right in that they can not cause damage.

I don't like the idea of flashing the BIOS to the 6970, but would people here think i will see an improvement by unlocking the shaders, as the card is already performing very will with all games i can throw at it and i would not like to reduce this......

Although the wattage is 250W, i would think the fan uses up most if this, or at least a good amount or am i wrong again? but 200+ amps sounds allot for a PCB to handle.

Thanks again...

Definitely unlock your shaders mate, its worth it for sure and i dont think that the fan uses much power at all

 

[jonny512379]

Is 1.3 volts safe? as i can get the core up to 950 at this voltage and temps are reasonably low.
My temps are a max of 68c under benching and gaming with an idle of around 52c (on stock cooler, with a case fan blowing onto the GPU too).

Thanks again for all the help
Jon

 

[chaotic_uk]

52c seems a little high for idle tbh

 

[ViRuS2k]

You should be able to run 900/1400 without even upping the voltage.
i use 1.215v for 950/1400 on my xfire setup and 1.260v for 1000core

24/7 though 950/1400 1.215v

anywhere from 800 to 900 though doesnt need voltage. also the power control setting in CCC is used if you go over the TDP limit, noticed useing furmark only to throttle 3d clocks
but in any other game just keep the power control setting at 0 or 8% only minimizes microstuttering aswell to a extent but even then thats for crossfire, your running single so you shouldnt need any at all..

 

[MOOGLEYS]

68c is very low when under load, Are you running a high speed fan profile ? Mine maxes at around 86.c but remains quite.

 

[ViRuS2k]

make sure you stick to your original bios with shader unlocked and overclock with only msi afterburner like i do

 

[ViRuS2k]

also 52c at idle is very high, i idle at 28c on 1 core and 31c on the other.

 

[jonny512379]

You should be able to run 900/1400 without even upping the voltage.
i use 1.215v for 950/1400 on my xfire setup and 1.260v for 1000core

24/7 though 950/1400 1.215v

anywhere from 800 to 900 though doesnt need voltage. also the power control setting in CCC is used if you go over the TDP limit, noticed useing furmark only to throttle 3d clocks
but in any other game just keep the power control setting at 0 or 8% only minimizes microstuttering aswell to a extent but even then thats for crossfire, your running single so you shouldnt need any at all..

I wish i could get the performance you get on them volts but for 900/1450 will not run on anything less than 1.2v.
I can get 950/1400 but only on 1.3v and anything over this 950 causes Heaven Benchmark to freeze the PC.
What make is your card or you have a very good quality one (mine is sapphire, maybe that's why OCuk have stopped selling them..... although they did recommend it to me over the XFX)

I am on a custom profile to keep the load temps down (i don't care much about fan noise if it saves the GPU or extends its life) but i can not get anywhere near your temps on idle, even on stock settings the card idles at around 44c with the fans at 40%.

To try and keep the voltage and the idle temps lower i have just set 930/1400 @ 1.25v. this keeps idle temps down to 48c (fan speed @ 40%) and load to around 60c (fan speed @ 60%) and all is stable.
I hope this is more of a recommended safe voltage and idle temps.

 

[ViRuS2k]

I recommend ASUS all the way.

and im running 2x asus oc+ 6950s @6970+ clocks with shaders unlocked.