I have came here from virtualbox forum also. I think the driver file is fine.
AMD driver works with any windows app including furmark and even VMWARE acceleration for 3D. I believe the problem is related to virtual box.
I also ran driver signature verification and the files seem to be fine. you yourself tested different versions of the drivers. If there were corruptions in the files, windows would give signature errors.
Looks like every half a year a new person comes with this.
I have the same issue, and posted on the same virtualbox forum topic created by yurtesen.
@ignis , I am not surprised that the problem was not fixed. I think VirtualBox eventually will become obsolete unless they change their behavior. I gave up on VirtualBox. If I remember correctly, they said virtualbox makes some extra checks on files and thats why it rejects AMD driver, which is BS. Because all other programs think the file is fine, even windows does signature checks and thinks the file is fine and everything else works fine!
I am sorry for the language and if you found my posts on other forums, I never use such language ever, but VirtualBox forum is the worst forum I have been to in my whole life. I try to give information to them and they reject it in favor of doing nothing. I am also sorry that I had to write this long unrelated response, you made me remember my VirtualBox forum experince after long time
Ther in their forum is a user 'socratis' who spoils everybody's experience and he does not even understand virtualbox. Everytime I ask a technical question he gives an answer which will make the user go away and do some useless work. Look at this, he got mad when I showed he was wrong:
virtualbox.org • View topic - Ubuntu 16.04 Guest Random Freezes
It is the only forum where I was threatened by "moderator" that I was behaving badly! 'socratis ' at VirtaulBox forum is just abusing his powers to make up to his shortcomings. I have better things to do than try to behave nicely to a**holes. (again sorry for the language).
I ran tests, produced empirical results, made screenshots and spent hours and hours of work to show them some facts. They also reject them in VirtualBox bug reports. (I think same people in forum are also managing bug reports)
So, to put it short. I tried to explain them many things, they will not do anything. This is why I think VirtualBox will become obsolete VMWare Workstation works much nicer. You can export your virtual machine from VirtualBox and import to VMWare. I think there were some format restrictions but it worked for me.
Sorry for reminding you about your socratis encounters
Yes, in the end I too gave up on VirtualBox for VMware, and now enjoy my KDE without any issues. So that indeed was a VirtualBox - AMD compatibility problem.
It is more like a VirtualBox problem. Because between all the game titles and other VM software, VirtualBox is the only one which rejects the driver. It is almost like they have something against AMD (or maybe getting paid by Intel? )
@ignis, no problem, I am happy to hear that you also left socratis behind