What is the best way to overclock Kepler with GPUs?
I don't think there is a "best" way to do it.
What i do is:
1. Get the best configuration possible using cuda miner
2. Set memory clock to the lowest possible point (Mine is -502).
3. Increase the GPU clock by 10.
4. Wait 15 mins to see if you have any errors
5. If no errors or driver crashes go to step 3 else go to step 6.
6. If there are driver crashes or errors reduce gpu clock by 10
7. Profit!
If you really want to oc kepler cards, you should use nvidia inspector to force a p-state (usually p2) and set a fixed clock there.
That´s the only way your card´s turbo boost won´t interfere with overclocking. (at least for 600series cards, not sure about 700)
Turbo boost causes fluctuating clocks, unstable hashrates, a decreased max overclock and more heat/power consumption.
To understand this, you need to know how turbo boost works.
Turbo boost 1.0 (which is used in 600 series cards) sets a gpu clock according to a clock table in the graphics bios.
It determines this clock by measuring the power consumption. Nothing else.
This means by increasing the max power consumption (aka power level %) the card will clock higher.
Additionally there´s the "clock offset" which is normally used to increase the gpu clock.
But this is not actually doing what you would expect it to. It doesn´t add a given value of Mhz to the Turbo boost clock table entries.
Instead it decreases the VOLTAGE the card uses for ALL entries in the Turbo boost clock table.
Which also means any "voltage offset" you find in an oc tool does absolutely NOTHING.
And since decreased Voltages result in lower power consumption, turbo boost then sets a higher clock from its table to reach the given Power level.
Sounds stupid to you? well, it works, but it´s not the best way to overclock a gpu.
So how do you use this better way mentioned earlier? (Windows)
1. Download nvidia inspector:
http://downloads.guru3d.com/NVIDIA-Inspector-1.94-download-2612.html nvidia inspector has a GUI, but it lacks one important feature we need. Thats why we use command line options.
2. make a batch file with these contents:
set "NVinspectorPath=C:\.........\nvidiaInspector.exe"
start /min "Nvidia Inspector - overclock" "%NVinspectorPath%" -setBaseClockOffset:0,0,160 -setMemoryClockOffset:0,0,300 -setpowertarget:0,153 -setVoltageOffset:0,0,0 -setGpuClock:0,2,1220 -setMemoryClock:0,2,3304 -setFanSpeed:0,80 -forcepstate:0,2
Obviosly replace the ...... with the path to where you extracted the program.
DO NOT simply run it that way. The values you see here are the ones I use for my 660Ti. You will need to adjust them.
These options always need to consist of multiple comma separated arguments.
The first one is always the device number for which you would like to set this.
For those with three arguments like "-setGpuClock:0,2,1220" the second one is the p-state it refers to.
Since we want to stop turbo boost from interfering, we need to use a different p-state where the clock is not controlled by turbo boost.
That´s what the -forcepstate:0,2 stands for. However even then Turbo boost is still on and in control of voltages.
That´s why we need -setBaseClockOffset:0,0,160. higher values will decrease voltages.
As i´ve said, -setVoltageOffset:0,0,0 is not what controls voltages. (you can delete this with nothing changing, this is only for other cards.)
-setMemoryClock:0,2,3304 actually doesn´t do anything either, for memory you always use -setMemoryClockOffset:0,0,300
And last but not least don´t forget -setpowertarget:0,153. This finally allows your card to use a set percentage of its specified TDP.
Without editing the bios you won´t be able to set a value of 153% like I do, but i´m just setting this so I can experiment with very high clocks.
For better understanding and tuning i recommend using the oc section of the GUI. It will also show your actual current clocks, temps, power consumption etc. You should also see that it says "P-state P2".
Now you´re set to optimize your OC to the max or set it to the best power-saving settings.
Also, this will help get much more consistent results for autotuning in cudaminer.
Happy OC-ing.
