Sapphire 7970 Overclock HELP !!!!

[Seqqsy]

Hi everyone,

First off, I would like to say that this is the first time I am overclocking my GPU which is a Sapphire 7970 that came with 950 Core / 1425 Memory Clocks + 1.2v.

I have been doing all the research I can over the internet about overclocking and I need your final advice to wrap my case up.

My first attempt was to install Sapphire Trixx which showed the voltage and what not. I tried to go with a 1100/1550 setup and it worked !. I spent 3 heaven benchmarks and got 70.4 fps - 1722 score - 69 C.

However everytime I tried to go up from 1100 core clock, heaven started to crash.

You see I am a complete fucking noob when it comes to voltage tempering therefore I installed MSI afterburner.

What I liked about MSI afterburner is that you can set up 20%+ and I managed to get a stable 1130 core - 1580 memory.

Now if I would like to go higher ( let's say aiming for 1200/1600)

a) should I use Sapphire Trixx and do what exactly with the voltage ?
b) should I change fan settings or leave it on auto ?
c) between trixx and msi, which one I should use or is there another program do you recommend
d) is there a secret formula to the ratio of Core to Memory speeds or is it more like ... you push core to the max before it fails ... you push memory before max it fails ... then you push the voltage and re-do the entire process ?

Please help and thank you <3

 

[Seqqsy]

The highest stable clocks I can achieve WITHOUT touching the voltages are;
Core - 1100
Memory - 1540
Power - 20+
Fan Speed - Auto

Is this normal for not-touching the voltages which is at 1.2v I think. I am trying to hit 1150 / 1200 and 1600 combination do you know how should I increase my voltage ? bit by bit ? by how much ? what is safe before going over board ?

Thank you

 

[iam2thecrowe]

unfortunately many of the 7970's that were reported earlier getting overclocks 1200 and beyond were crippled with newer boards when they put hard volt limits and board power limits in place. I cant get mine stable over 1100 either. Some boards can be bios flashed to get a little more voltage, but ive also read, even though it reports a certain voltage in trixx or whatever, it may not actually be doing anything on the board, or getting vdroop due to cheaper vrm's used on some boards. Trixx was the most stable program i found, and it could adjust voltage up to the bios hard limit. You can change power limit in AMD catalyst and still use trixx.

There is an overall PCB power limit that is hard fixed though and you cant change it, so yeah you can only take the ram + gpu so high before it throttles that. I suggest getting the gpu overclocked, then get the most you can out of the ram, as its already high bandwidth ram. If you find you can only get the vcore voltage so high, you could look to see if there is a compatible bios with more volts, assuming you have the dual bios switch on your gpu, its pretty safe to do. I found i could flash the ghz edition bios to my 7970 to get slightly more volts and better gpu OC, but had to dial the ram speed back to get stable.

Hope that helps some, but if i were you i'd sit pretty happy on that 1100mhz OC, that is all some chips are capable of.

 

[Seqqsy]

Thank you for the quick response. Honestly, like I mentioned before, I am pretty new at this whole OC-ing scenery and from what I can comprehend and do nothing above 1100 Core Clock seems to work. Even 1105 core - 1540 memory - stock voltage at 1.2v crashes on heaven.

The thing is I have the fan settings on auto. Should I crank that up to 70% ~ for the sake of stability testing ? If not .. not sure about the whole dual bios or w.e that thing you mentioned.

What I don't understand is that ... the same clock speeds on Trixx doesn't work with heaven but works with MIS. Is that because MIS has that 20+ Power limit feature ? I wanted to play with the voltage setting on Trixx but I am clueless sooooooo I wouldn't even know by how much should I increase the voltage.

 

[iam2thecrowe]

1.2v isnt enough. if trixx cant increase volts to somewhere near what the 7970GHZ editions run (1.275v from memory) then your not gonna get past 1100. I was the opposite, found msi afterburner provided worse overclock, and i couldnt get voltage control with it. Get gpuz too, it can monitor your actual vcore voltage, and if your lucky you will have vrm temperature sensors (mine doesnt) to ensure the extra volts isnt making them too hot.

 

[Seqqsy]

1100/1540 @ 1.2v is what I am running atm and underload it gives me 70 C.

Is OC about clocking it higher to a point where it is stable and still is under 80 C ? Like how far should I push the card in terms of temperatures ?

 

[iam2thecrowe]

1100/1540 @ 1.2v is what I am running atm and underload it gives me 70 C.

Is OC about clocking it higher to a point where it is stable and still is under 80 C ? Like how far should I push the card in terms of temperatures ?

depends, how high is the fan speed at 70c? is it at max fan speed? you want to try keep it as cool as possible, will aid in stability. i think 80c is about the most you would want to go, if your overvolting, then keeping temps lower to avoid damage. Also if you have access to vrm temps, check those, as they can fry before anything else. GPUz should monitor their temps if your board has sensors for them.