Quote from: Mythic on October 27, 2017, 12:13:30 PM

I hadn't originally planned on putting this out there, but some other asshole decided to charge a fee for this info. Fuck that guy. Here's a fix for reduced hashrate and a method for running 4+ Vega at full speed while mining XMR.

Basic Users:

1. Use the Blockchain drivers.
2. Open up your device manager.
3. Open up the "Display Adapters" dropdown.
4. Right click on one of your Vega's.
5. Disable it.
6. Wait a few seconds.
7. Right click on the Vega you just disabled.
8. Re-enable it.
9. Repeat steps 4-8 for the rest of your cards.
10. Enjoy mining at full speed with as many Vega as you damn well please. Probably.

Advanced Users:

The previously described process is a bit of a pain in the ass. Let's automate it.

New Procedure

1. Get your hands on the Windows Device Console (Devcon.exe). This will let you disable/enable devices from console.
2. Create a batch file in the same folder as devcon.exe with the following lines in it:

Code:

cd %~dp0
timeout /t 5
devcon.exe disable "PCI\VEN_1002&DEV_687F"
timeout /t 5
devcon.exe enable "PCI\VEN_1002&DEV_687F"

3. This will selectively disable/enable all the Vega cards you currently have in your system. Thanks to bytiges for noting that killing all the display adapters might not be a good idea for those using iGPU.
4. Run the batch file as an administrator at login, or whenever you lose hashrate on your cards. Enjoy never having to toggle the HBCC switch again.

Outdated Procedure

1. Get your hands on the Windows Device Console (Devcon.exe). This will let you disable/enable devices from console.
2. Run the command devcon.exe FindAll * to generate a list of all the currently attached devices and their hardware IDs.
3. Search your newly generated list for "Radeon RX Vega." You should find something like this:

Code:

PCI\VEN_1002&DEV_687F&SUBSYS_0B361002&REV_C3\6&3AAC35E3&0&000000E7 : Radeon RX Vega

4. The part to the left of the colon is what you need. Shocking, I know. Put that thing into a batch file that looks something like this:

Code:

@echo on
cd C:\Users\Mythic\Desktop\Startup
timeout /t 5
devcon.exe disable PCI\VEN_1002&DEV_687F&SUBSYS_0B361002&REV_C3\6&3AAC35E3&0&000000E7
timeout /t 15
devcon.exe enable PCI\VEN_1002&DEV_687F&SUBSYS_0B361002&REV_C3\6&3AAC35E3&0&000000E7
timeout /t 15
OverdriveNTool.exe -p0Vega0 -p1Vega1 -p2Vega2 -p3Vega3 -p4Vega4 -p5Vega5 -p6Vega6
timeout /t 10
cd C:\Users\Mythic\Desktop\xmr-stak-amd
xmr-stak-amd.exe

5. Run your batch file at startup as an administrator. Enjoy never having to toggle the HBCC switch again.

FAQ:

Q: So, Mythic, how exactly does this enable HBCC on cards 5-7?

A: It doesn't! HBCC Does nothing to improve your hashrate! Turns out the drivers are just shit and are bugged when Windows first boots up. Who would have guessed?

Q: But Mythic, does that mean I don't need 16 GB of ram to run my cards at full speed?

A: Correct! 4 GB of ram is completely sufficient!

Q: If I wanted to donate some pizza money to the broke ass college student that typed this up, how would I do so?

A: You ask the best questions! I doubt I'll get anything before more well known people/websites copy everything I just said (with no credit, obviously), but here are some addresses just in case.
XMR: 42e8AWjcirkBDzCNnSjPxeGJeht71kFfWcoxxCWsxe8HZqP29NruDsxcvVSjbKw17AUDepopK7ZYCUn mRvcGS9kBT5XWhMQ
ETH: 0x74Ed2CA095Dd3aE98D88d5ca1dDb77E752152938

Thanks for the great solution which I've been searching for!
However I'm using 2 Vega56 just 1 is unable to switch HBCC.
I tried your manual method disabled "HBCC non-switchable Vega56" got exclamation mark on it. Then it couldn't be enable...
To see Radeon setting aimed Vega was missing same as turn on/off HBCC.
I've already clean uninstall driver AMD/DDU and reinstall blockchain driver several times.
running on Win10 64, ASRock H270 Pro4, 8GB DDR4 mem, 16GB vmem, Celeron G3930, SSD 120GB

Hope someone knows solution!

gldi0001

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