OCTune
Use OCTune. Look for values Min KT and Avg KT. Your goal is to get these values as low as possible. What is the meaning of these values? KT = Kernel Time. It is execution time of code running on GPU in microseconds. Min = minimal time (in previous X runs) and Avg = average time. Min can sometimes drop down to half of usual - you should ignore these values.
1. Find your max memory clock
First, you should find your max memory speed or determine at what memory speed you are prepared to run your GPU. Higher power limit and lower core clock can help memory stability. Therefore, set power limit to some high value (can be at 100% of your TDP - note the value needs to be in Watts!) and core clock to -600. Then increase memory clock by 25 each step and test at least several minutes. There should be no HW err and make sure there are at least 3 accepted shares on that card (HW ok increases by 3 at that speed). Once you find your max memory clock, you can go to step 2.
2. Reduce power limit
Now you can start reducing power limit. At some point, Min KT and Avg KT will start rising. That is a sign that you need to back off and stop reducing power limit (temporary). Now you need to increase core clock. Go to step 3.
3. Increase core clock
Increase core clock +25 at a time until your Min KT and Avg KT stop improving (values do not go lower anymore). Note that higher core clock can affect stability of your memory. You may have to decrease your memory clock if there are rejected shares (share above target) and value in HW err increases. Once you find ideal core clock, you can again try with reducing power limit.
4. Play with settings to achieve best KT values
You have to fiddle with core clock, memory clock and power limit until you find best KT values (lowest) and max stability (no shares above target - HW err stays at 0). Once you find best values, you will have the highest possible speed. You can save your OC configuration (click Save current configuration) so it will be applied next time Excavator is started.
Note: This feature is currently available only in RC version of NiceHash QuickMiner which can be obtained here.
With version 0.3.0.4 alternative overclocking ability was added to NiceHash QuickMiner. With this method, you only need to provide two values to optimize your mining efficiency:
- absolute max core clock of video card,
- absolute memory clock of VRAM and
- fan speed (optional).
For comparison, UI is displayed here (1 is old classic method, 2 is new alternative method):
There are some differences and rules:
- You cannot use both OC methods at the same time. Whichever method is used last is applied and saved in
commands.json(if wanted). - Alternative OC resets TDP to default value of 100%. Your power limit entirely depends on configured core clock and memory clock of your video card.
- There is minimal core clock (210) for all cards.
- Alternative OC may not work on all NVIDIA series cards (but works confirmed on series 3000 and 2000).
- Alternative OC is the only way to optimize Quadro and Tesla series as these cards do not support changing delta core and delta memory clocks.
First, find max stable memory clock of VRAM. Generally, following memory clocks can be achieved on most of video cards:
| GPU Model | Absolute memory clock | Delta memory clock |
|---|---|---|
| 3060 Ti | 7900 | +1100 |
| 3070 | 7900 | +1100 |
| 3080 | 10300 | +850 |
| 3090 | 10350 | +850 |
If you are getting rejected shares of type Share above target then your memory clock is not stable and you have to reduce it. But generally, if you get one or two bad shares of such type per day, it is still okay.
Once you find max stable memory clock, start with high Core clock limit (like 1800 for example) and start decreasing it, observing Speed (MH/s), Power Real (W) and Eff. (kH/J) (efficiency).
After each decrease of Core clock limit, check values Min KT, Avg KT and UMed KT. These values should go as low as possible. The lower they are, the better speed you have. Once you are happy with the achieved speed, you can save your OC configuration by pressing Save current configuration button at the top. Note that if you change your memory clock, you'd need to readjust Core clock limit but usually not for much (perhaps only +15 or -15).
Highest possible efficiency makes your video card use less electricity, produce less heat and wear&tear while still maintaining almost max possible speed. Here, you should do reverse, start with lowest Core clock limit and increase +15 at a time. Observe how KT values are falling down. At one point, you will notice that KT values do not change much with further increases of Core clock limit. That is the time to stop. Job done. You can save your OC configuration now.
While testing few cards, we managed to achieve following numbers:
| GPU Model | Absolute memory clock | Core clock limit | Power consumption (W) | Speed (MH/s) | Efficiency (kH/J) |
|---|---|---|---|---|---|
| 3060 Ti | 7950 | 1350 | 120 | 60 | 500 |
| 3070 | 7950 | 1050 | 117 | 60 | 513 |
| 3090 | 10401 | 1080 | 286 | 117 | 411 |