My 780 classified overclock

WillSK

Active member
Hey guys.

Decided to have a proper play with my classified recently to really get that power out of it and the following is what i currently have. Have played a long round of BF4 and also ran several benches in Haven giving me a score of between 1677-1679 so I think it's stable.

Just wanted to get your opinions as I have no idea what a good overclock is for these cards and I know a few of you guys are running them and similar. Are the voltages sensible, speeds a good clock and so fourth? Also do i wanna be prioritising temp or power target?

Thanks in advance

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Seems legit and very close to what mine run at when pushing hard. I haven't overclocked them individually yet so I don't really know the true limit but found they were happy running benchmarks at 1241/1728, they will do 1267 with a voltage increase, I probably should update my precision-X as this one I have isn't the best for overvoltage.

Anyway I hope that it helps and it sounds like yours is running strong. For 24/7 use I backed mine down to +125 with stock memory and volts then I just apply the aggressive profile for e-peen but it's not really noticeable in games. For the power/temp target I unlinked them and max out the temperature target and dropped the temp target although it's not really relevant as they are underwater. I've noticed they do suck a lot more power now they are underwater but G-Sync also makes them work harder in all fairness.

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JR
 
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Cheers JR so my 1212mv voltage setting shouldn't be an issue?

I have to admit it's voltages that confuse me coz in gpu-z it shows max VDDC as 95.750v which i have no idea what that means or if it's a mis read but doesn't resemble 1212 in any way hence my confusion
 
I don't really know, my Precision-X which is quite old has a voltage offset option and it only allows +50mV on the stock BIOS, as you can see in HWMonitor it seems they are maxing at only 0.937mV, well under 1212mV. Whenever I overvolt too much they seem to become less stable which I though was probably down to Precision-X being a bit weird. VDDC is memory voltage isn't it? GPU-Z looks to be reporting that correctly.

JR
 
I have a friend who runs at 1400+ on air with one(never really pushed it on water,yet),and it will be mine soon.....


tbh less than 1300 on a classy is pretty bad tbh,you can get reference cards to that level if you push them hard enough,the whole point of a classy is to be MUCH higher than a reference.

Go hard or go home,you are not even pushing the card,you may as well have a stock card.

Use the voltage tool to get 1.35V(or with the EVbot up to 1.5+) and see what it gets or sell it
 
I have a friend who runs at 1400+ on air with one(never really pushed it on water,yet),and it will be mine soon.....


tbh less than 1300 on a classy is pretty bad tbh,you can get reference cards to that level if you push them hard enough,the whole point of a classy is to be MUCH higher than a reference.

Go hard or go home,you are not even pushing the card,you may as well have a stock card.

Use the voltage tool to get 1.35V(or with the EVbot up to 1.5+) and see what it gets or sell it

ok so it's safe to set at 1335Mv? and then try and crank to 1300? How's 600 looking for the memory?

Are artifacts always the sign of an overclock gone too far or could they appear if there is not enough voltage? Just wanna know what i'm looking out for. What kinda voltages are safe for an every day overclock? Sure i'd love to see what the card is capable of but i don't wanna over do it

Cheers dude!
 
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That's what I run my Titans at, watercooled.

1300MHz and 1.32V

Yeah keyword being watercooled. I could probably run it on the aggressive fan profile and be fine but on the auto (quieter) profile we're looking at 82 degrees +

I really need to venture into watercooling one day. I envy you guys!

One thing I don't quite understand is the correlation between the voltage i set and the 115% power limit. Does this mean the voltage will go 15% higher than what i set? if so that's bad!

Another il gpu overclocking question I don't get is how people describe their memory overclocks i.e.

1 person will say overclocked to say 1800mhz (what i see in precision)

1 person will say 3600 (what the ram is running at right?)

1 person will say a number over 6000 (what are they talking about?)
 
Yeah keyword being watercooled. I could probably run it on the aggressive fan profile and be fine but on the auto (quieter) profile we're looking at 82 degrees +
I really need to venture into watercooling one day. I envy you guys!

I only watercooled just over a year ago but it lets me run those speeds/voltages 24/7 without breaching 55 degrees GPU temp.

One thing I don't quite understand is the correlation between the voltage i set and the 115% power limit. Does this mean the voltage will go 15% higher than what i set? if so that's bad!

The power limit is based on the wattage of the card (this is denoted in the VBIOS), so for instance if your card is allowed to draw 300W, then 100% power limit will allow 300W, 115% will allow 345W and so on. The only correlation to voltage is that voltage is directly related to wattage. The more voltage you allow through, the more watts it consumes.


Another il gpu overclocking question I don't get is how people describe their memory overclocks i.e.
1 person will say overclocked to say 1800mhz (what i see in precision)
1 person will say 3600 (what the ram is running at right?)
1 person will say a number over 6000 (what are they talking about?)

Forgive me if this is wrong and please correct me, but the first figure (1800) is the speed you are adding onto when you overclock, so if you add 100MHz, that will go to 1900Mhz. The middle figure (3600 in your example) is because it is double data rate and therefore the speeds are effectively doubled.

The last figure is because GDDR5 actually works differently to DDR3 (which it is based on), in that it controls input/output in the same cycle, therefore doubling the effective clock again. DDR3 does not do this and controls IO on separate cycles.
 
I only watercooled just over a year ago but it lets me run those speeds/voltages 24/7 without breaching 55 degrees GPU temp.



The power limit is based on the wattage of the card (this is denoted in the VBIOS), so for instance if your card is allowed to draw 300W, then 100% power limit will allow 300W, 115% will allow 345W and so on. The only correlation to voltage is that voltage is directly related to wattage. The more voltage you allow through, the more watts it consumes.




Forgive me if this is wrong and please correct me, but the first figure (1800) is the speed you are adding onto when you overclock, so if you add 100MHz, that will go to 1900Mhz. The middle figure (3600 in your example) is because it is double data rate and therefore the speeds are effectively doubled.

The last figure is because GDDR5 actually works differently to DDR3 (which it is based on), in that it controls input/output in the same cycle, therefore doubling the effective clock again. DDR3 does not do this and controls IO on separate cycles.

Really appreciate this! thanks

How on earth did you stay at 55 degrees overclocking to over 1300Mhz. What voltage do you have set and are you using a very aggressive fan profile?? Or do you mean 55 degrees under water?
 
Really appreciate this! thanks

How on earth did you stay at 55 degrees overclocking to over 1300Mhz. What voltage do you have set and are you using a very aggressive fan profile?? Or do you mean 55 degrees under water?

Yeah 55 under water :) They were around 90 on air.
 
I've been benchmarking my Classifieds again over the past day or two and have found a few extra MHz. CPU stayed at the same 4.7GHz throughout with no system changes aside the cards. The combination of the stock BIOS and PrecisionX limit me to 1.3v however when running both cards they get so power hungry my PSU limited me to about 1.287v anyway so I won't bother modding them. Both cards will manage the same core clock at 1.3v but the Samsung card has much stronger memory. Also to get the Hynix stable at 1345MHz I had to drop the memory down a notch from my SLI profile but the faster core did reflect in a slight fps improvement so it was worth it. As a pair they are quite impressive although there is no doubt that having two Samsung cards and a bigger PSU would yield massive improvements. Daily though I just run the stock 1124/6000 as games don't seem to appreciate the effort of overclocking.

Both cards - 1333Mhz Core 6858MHz Memory

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Hynix card - 1345MHz Core 6848MHz Memory

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Samsung card - 1345MHz Core 7208MHz Memory

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JR
 
What do you use to set/monitor the voltages? I've come to realise that what i set in Precision X isn't always read by the software. i.e. I don't REALLY know how many volts are going into my card reliably
 
What do you use to set/monitor the voltages? I've come to realise that what i set in Precision X isn't always read by the software. i.e. I don't REALLY know how many volts are going into my card reliably

I used PrecisionX there is a voltage in the monitoring and GPU-Z that seem to reflect it so I thought it was legit. It definitely had an effect on stability and power consumption :D

JR
 
I used PrecisionX there is a voltage in the monitoring and GPU-Z that seem to reflect it so I thought it was legit. It definitely had an effect on stability and power consumption :D

JR

Yeah i've resorted to GPU-Z ad you're right the number seems a bit more reliable in there. Your are under water though right? I've actualy dialled my OC down a bit as my temps were getting pretty high
 
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