2,5 months ago I've encountered SVM mode bug which leads to unexpected bios behavior since some of the bios settings are completly getting ignored.
For example UMA Frame Buffer Size. When setting UMA Frame Buffer Size to 64MB and SVM mode is enabled the AGESA loads the defaults parameter values when using Hyper-V. This cause 2GB assigned instead of the 64MB configured
After two weeks of troubleshooting with MSI we reached the same conclussion. The AGESA contains a bug which leads to this unexpected and unwanted behavior. They would contact AMD about this issue and asked me to create a Service Request at AMD aswell.
So I created a Service Request about the SVM mode AGESA bug.
This is my AMD Global Customer Care experiance untill now:
- Service Request #1
- Got a link from AMD Global Customer Care with the request to fill a bug report for the AMD Adrenaline driver.
- I've filled the form and informed them it isn't an AMD Adrenaline driver bug but AGESA bug which needs to be investigated by an AGESA engineer.
- Almost two weeks had passed and still didn't got any response so I send a reply and asked them for a status update.
- Exact two weeks later without any response the Service Request got closed. (Almost a month has passed since creation of the service request)
- Service Request #2 (Created new request and pointed out I was still waiting on the response of AMD Global Customer Care on the previous Service Request)
- AMD Global Customer Care asked my about information which I already provided in the previous Service Request.
- I've replyed the information about brand/model and firmware could be found in the previous Service Request and I refused to repeat myself.
- First week without a response. Send a reminder I was still waiting on a response and quite disappointed how AMD Global Customer Care is handling the request.
- Second week without a response. Send a gentle reminder since there was still no response.
- Third week without a response. Send a reply informing them I am already waiting 1,5 month on AMD to acknowledge this issue and if I wont get a response I would post it on the AMD community forums so people are aware this issue exists and AMD doesn't undertake any actions to repoduce it at all.
- Forth week still no reponse so I send a mail again which I state I would post it on the AMD community forums if there is no response within a week.
- Another week has passed without a response which caused the creation of this topic :-)
In the last two months MSI also didn't get any response from AMD on their side aswell....
Motherboards where the SVM Mode issue is reproduced:
- MSI B350 Tomahawk (Bios version 1OR)
- ASUS ROG-STRIX-B450-E-Gaming (Bios version 3004)
Processor used:
Reproduction steps:
Phase 1:
-Bios reset to defaults
-Clean installation of Windows 10 1909
Phase 2:
-Set size of UMA Frame Buffer to 64MB
-Save bios settings and reboot
-Boot into Windows
-Check with CPU-Z or with GPU-Z the graphics memory
Conclusion: UMA Frame Buffer is 64MB
Phase 3:
-Set SVM Mode to Enabled
-Save and reboot
-Boot into Windows
-Check with CPU-Z or with GPU-Z the graphics memory
-Start taskmgr and check physical available memory
Conclusion: UMA Frame Buffer is still 64MB and hardware reserved memory matches with the amount of UMA Frame Buffer assigned in the bios.
Phase 4:
-Enable Hyper-V on Windows 10
-Reboot system and boot into Windows
-Windows is prompting a Window with "Your hardware settings have changed. Please reboot your computer for these changes to take effect."
Conclusion: Hyper-V will be fully enabled at the next boot.
Phase 5:
-Reboot system and boot into Windows
-Check with CPU-Z or with GPU-Z the graphics memory
-Start taskmgr and check physical available memory
Conclusion: UMA Frame Buffer size changed and amount of hardware reserved memory changed as well. UMA Frame Buffer is no longer 64MB but 2GB without changing the bios setting!!!
Phase 6:
-Reboot system and boot into BIOS
-Verify if UMA Frame Buffer size is still configured as 64MB
-Boot into Windows and start taskmgr
Conclusion: UMA Frame Buffer size is still configured as 64MB in BIOS
Phase 7:
-Disable Hyper-V on Windows 10 and reboot into Windows
-Check with CPU-Z or with GPU-Z the graphics memory
-Start taskmgr and check physical available memory
Conclusion: UMA Frame Buffer size and amount of hardware reserved memory are still wrong (2GB)
Phase 8:
-Shutdown PC and remove power cord for 1 minute
-Boot system into Windows
-Check with CPU-Z or with GPU-Z the graphics memory
-Start taskmgr and check physical available memory
Conclusion: UMA Frame Buffer size and amount of hardware reserved memory are still wrong (2GB)
Phase 9:
-Reboot system and boot into BIOS
-Disable SVM Mode
-Save bios settings and reboot
-Boot system into Windows
-Check with CPU-Z or with GPU-Z the graphics memory
-Start taskmgr and check physical available memory
Conclusion: Disabling SVM Mode resets the issue and cause UMA Frame Buffer size and amount of hardware reserved memory to match the configuration..
Root cause: Very likely AGESA bug since the issue is repoduced on a different brand motherboard aswell.
