Topic: VEGA 64 - Cannot Enable HBCC on 2/6 cards in rig after reboot. - page 3. (Read 5726 times)

I think your cpu is not a problem. The problem can be the way how motherboard bios or windows decided to connect you 5-th or 6-th gpu to the system - directly to cpu pci-e lanes or to southbridge switch.

I don't know if it is our case but you can read here https://github.com/RadeonOpenCompute/ROCm
Search for Supported CPUs chapter

Hmmm.  I suppose this is some important info given your response.

Mobo:
MSI Z270-A Pro ATX LGA1151

CPU:
INTEL® CELERON® Processor G3930

Perhaps the CPU is the problem?

It can be that HBCC technology only supported by modern cpu's pci-e lanes (ryzen, modern intel) and can have problems if used with chipset pci-e lanes ... just a guess ... I've read something from AMD documentation ...

More info.

So the two problematic cards are plugged into PCI-E 3.0 1x slots (#2 and #3 on my mobo in order from top to bottom).

So I swapped a working HBCC card with one of the ones that I cannot enable HBCC on.

It seems whichever two cards are plugged into these PCI-E slots are problematic as the swapped card now cannot enable/adjust HBCC.

So I verified this a few more times.  It appears whatever two cards I have plugged into the #2 and #3 pci-e slot cannot enable HBCC. 

This problem also goes away entirely if I just run 4 GPUs, then those slots are fully functional.

I'm really stuck trying to diagnose this problem.

The problem is straightforward to describe.  I have 6xVEGA 64s.  I go to Wattman to enable/adjust HBCC for each card.  When I click "apply" the screen will flicker once and the setting will take.  However for 2/6 of the cards it just crashes Wattman.  When I open Wattman up the setting remains unchanged for that card.

At one point all cards were working fine.  It was not until I rebooted that I got into this state and now I cannot get out of it.

It gets a bit weirder.  I've tried the following on both the latest blockchain drivers and the latest non-blockchain drivers. 
- Safe Mode
- DDU, remove all (also tried same steps with AMD Clean Utility)
- Boot with 1 GPU
- Install drivers
- Shutdown, connect another GPU, boot, wait for drivers to see new card
- repeat last step until all 6 cards are working

Again 2 cards will unable to adjust HBCC.  I get no error message, no details as to why, the setting just refuses to adjust for two of the cards.

I am running:
- Windows 10
- 32GB RAM
- 64GB Virtual Memory (required for xmr-stak-amd setup getting 1900H+).


Question:
- Is there an error log AMD spits out I can try and look at?
- Windows records no event logs when HBCC adjustment causes Wattman to crash.
- Bios issue?
- What if anything can I do to continue to diagnose this?

Any other info I can provide to help others help me?

TLDR; Help me please! My rig is short 1200H because two cards won't enable HBCC.