Do you guys have same problem? After rebooting often i need to reboot gpus using devcon app couple of times. Often after first or second hashrate has tendency to drop.
enable and disable the Vega GPUs in the Device Manager in Windows if you need to restart them 'cos of a hashrate drop. (never use the HBCC toggle of AMD Wattman, it's crap)
Also
http://vega.miningguides.com/ is great to learn how to disable Crossfire and
set virtual memory in Windows, large pagefiles, etc.
Other additional AMAZING tips:
Step 1: Configure BIOS SettingsBefore we even get to Windows, make sure your mining computer’s BIOS settings are in order. Power on your computer, and press the “delete” key a few times immediately after power on. You should end up in the BIOS configuration area. Do the following, then save & exit:
Change power options so that the computer automatically turns itself on whenever power is restored. The reason for this is two-fold: first, it’ll make sure that your miner automatically starts up after a power outage. Second, it makes powering the computer on much easier if you don’t happen to have a power switch connected to the motherboard.
Disable all components that you don’t plan to use. This might save a little bit of power, and since your miner will likely be running 24/7, it’ll add up. For me, that meant disabling onboard audio, the USB 3.0 ports, one of the SATA controllers, the Firewire port, and the serial port.
If you’re running a lot of GPUs (4+), additional tweaks might be necessary to ensure that they’re all recognized by the OS. Exact tweaks vary by motherboard, but setting the PCIe speed to Gen1 is usually a good place to start. No need to change anything now, but make a mental note that you may need to come back and play around a bit if all of your GPUs don’t show up in the OS later.
Step 3: Configure automatic loginIf you’re building a dedicated mining rig, then you probably want your mining rig to boot up and start mining automatically, without any user intervention. We’ll need to enable auto-login for that to be possible.
Right-click on the Start Menu and select “Run”. Type “netplwiz” (without the quotes) at the prompt, and click “ok”.
Uncheck the box that says “Users must enter a user name and password to use this computer”.
Click “Apply”. You’ll be prompted to enter your password to confirm the change.
Step 11: Configure your miner to start automaticallyWe want our rig to automatically start mining whenever it’s powered on or rebooted. That way, we keep mining losses to a minimum whenever a power outage occurs, and we don’t have to worry about manually starting it back up in other situations.
Open Windows Explorer and navigate to the folder where you created “mine.bat” in the previous step.
Right-click on your mine.bat file, and pick “Copy”.
Now, navigate to %AppData%\Microsoft\Windows\Start Menu\Programs\Startup (should be something like C:\Users\[YOUR WINDOWS USERNAME]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup).
Right-click anywhere on the empty background of the Startup folder and select “Paste shortcut”.
You should see a shortcut to your mine.bat file appear in the startup folder. Windows should automatically execute it upon bootup.