I recenty assembled a pc with an ASROCK A320M-HDV R4.0 and a Ryzen 5 3400g. I updated the bios to the latest one (version 4.00 with AMD AGESA Combo-AM4 PI 1.0.0.6). It supports picasso cpus from 2 versions ago 
. Latest chipset drivers and 20.9.1 (WHQL) and 20.9.2 radeon drivers were tried. The OS in use is Windows 10 pro workstation x64 1909 patched to June 2020. The problem is that the pc either freezes in direct X applications or throws blue screens (not green) with DRIVER STUCK IN THREAD or IRQ LESS etc. in ati driver files. Also, some HDMI monitors do not work (I tried 3 different ones, 1 did not work at all, 1 gave black screens sometimes and 1 worked nicely, apart from the freezes that probably have nothing to do with the monitor but with the driver). All monitors work when connected to VGA and DVI.
For the HDMI monitor problem, I think that the AMD AGESA firmware is to blame. The HDMI UEFI driver does not play well with some monitors and TV monitors. I have seen other people having problems with certain HDMI monitors and they solved them by switching monitors, something that does not qualify as a solution. I think the next agesa update needs better HDMI init drivers.
For the freezing in DX applications, i tried the following:
I ran prime95, furmark and all the unigine benchmarks, sometimes together. The CPU part is rock stable. The GPU part sometimes freezes in Unigine and furmark (and games like Fortnite and minecraft). The memory is checked, the power supply is ok, so I tried to troubleshoot the driver.
I tried:
1) disabled IOMMU in bios (and csm)
2) disabled 'EnableULPS' in registry (from 1 to 0)
3) I played with the Tdr window values. Initially, I used 'TdrLevel' = 0 (disable), which made the GPU freeze IMMEDIATELY, so I switched it back to 3 (default- ON). Then I increased all the time values ALOT (for example, I put 'TdrDelay' to 12). Increasing all the time values made the GPU FAR more stable. It freezes usually after a cold start maybe 1 out of 4 times.
I also made furmark run automatically on startup. It does not freeze anymore but it sometimes blinks. If it blinks, other DX apps WILL freeze. I discovered that if I run it until it finishes a 12 sec benchmark without blinking, other dx apps will work normally 99% of the time.
Ryzen 5 3400g is an AMAZING cpu. Extreme value for money. It is a shame to bring its value down due to problematic vega 11 initialization in the AGESA and in the radeon driver.
Thank you for your time.
