GTX 1060 downclocking under Ubuntu 16.04 with Driver 390.30 and Cuda 9.1

Hi. I’ve realized that I bought two gtx1060s with Hynix memories for same price with the one with a Samsung memory. And unfortunately they’re not working at same performance.

Here is details of the problem (Interresting discovery on low hashrate GTX 1060):
https://github.com/ethereum-mining/ethminer/issues/314

Samsung one (GPU0) works better even with limiting its power:

+-----------------------------------------------------------------------------+
| NVIDIA-SMI 390.30                 Driver Version: 390.30                    |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GeForce GTX 106...  Off  | 00000000:01:00.0 Off |                  N/A |
| 25%   55C    P2    58W /  60W |   2780MiB /  3019MiB |    100%      Default |
+-------------------------------+----------------------+----------------------+
|   1  GeForce GTX 106...  Off  | 00000000:04:00.0 Off |                  N/A |
| 41%   68C    P2   105W / 120W |    506MiB /  3019MiB |    100%      Default |
+-------------------------------+----------------------+----------------------+
|   2  GeForce GTX 106...  Off  | 00000000:05:00.0 Off |                  N/A |
| 43%   71C    P2   108W / 120W |    506MiB /  3019MiB |    100%      Default |
+-------------------------------+----------------------+----------------------+

And I’m getting 20 Mh with GPU0 and 15 Mh per card with other two.

How can I downclock the card with this driver?

Driver version is automatically updated with Cuda 9.1.

I’ve seen some people succeeded before,

  • https://noobminer.xyz/overclocking-multiple-nvidia-graphics-card-linux/
  • https://www.reddit.com/r/EtherMining/comments/6jzvye/finally_got_headless_ubuntu_with_nvidia_going/

Also I’ve succeed it with previous versions of driver before too.

Thanks.

[s]Also with this driver, even with doing this;

sudo chmod 444 /etc/X11/xorg.conf

Something overrides xorg.conf changes at boot.[/s]
With using

chattr +i /etc/X11/xorg.conf

it stays safe. but I can just overclock the first gpu. Probably I need to create fake screens but, I don’t know how to make it work with 1 real monitor and 2 fake ones.