This product has long been EOL'd and has very limited Windows 10 support.
There is an just one Windows 10 driver which can be selected and downloaded from www.amd.com/drivers .
You should also keep in mind, FirePro cards are designed for professional graphics applications. not gaming.
First of all, thank you for replying!
Yes, I'm aware they are not designed for gaming. The problem here is that the game that worked at 150FPS before, isnt working anymore. Alright, it has limited support for Windows 10. But why would this problem also happen for Windows 7 ? The graphic card not working properly with the latest driver but with an older one. This seems really weird...