CRT Emudriver issue on cold boot

[Pixeljunkie]

Hi everyone

I recently jumped ship from regular MAME to GroovyMAME and I am very pleased with the results

However, I am experiencing a weird issue that i'm not able to solve. When I cold boot the pc, I get this weird lines
and artifacts (if you can call them that) when launching GroovyMAME. Worth mentioning that the Windows desktop is also behaving weird,
text and icons are not pictured properly. So it's not related to GroovyMAME.

The 'solution' is simple : reboot the computer and it's solved. As soon as I power down, the issue is back however 

I made a YouTube clip about it : cold boot produces the issue & reboot fixes it


I followed these instructions to the letter to install my card :
https://geedorah.com/eiusdemmodi/forum/viewtopic.php?pid=1052#p1052

I also tried the tutorial the guys from arcade express provide, but with the same result :


The card is a Radeon HD8940 flashed with Atom-15 BiOS :
https://www.arcadexpress.com/en/arcadevga/268-tarjeta-grafica-arcade-vga-1gb-gddr5-pci-express.html?_gl=1*cczdw1*_up*MQ..*_ga*NzU0MzUzNDYuMTY4MTg0MDE2NQ..*_ga_1T7JZJP32D*MTY4MTg0MDE2NC4xLjEuMTY4MTg0MDE2OS41NS4wLjA.

I have tried connecting the pc to 2 other CRT's, same results. But that shouldn't really matter because a simple reboot fixes the issue.
When i'd have to take a guess, i'd say that the driver doesn't load properly or something ? Windows is in Test mode, and I disabled secure boot in the BIOS.

Does anyone have an idea please ? I'm also getting the "error trying to fill the monitor range with" from Switchres, but that's probably because i'm only using the super resolutions (15 modes)

Thanks in advance to anyone willing to help 

[R-Typer]

perhaps you have Hibernate enabled? Fast Startup must be disabled on windows 10

[Pixeljunkie]

perhaps you have Hibernate enabled? Fast Startup must be disabled on windows 10

Unbelievable..i'm tinkering for 2 days to solve the issue and you fixed it by making me disable 'Fast Boot' 
I'm really thankful dude

Any idea on how to resolve the switchres error too ?