Virtual box is slow and buggy and it probably will always be that way. It is simply the nature of its design.
Qemu can also be used with KVM, without emulating the entire hardware. My preferred way to virtual machinery.
From linux-kvm.org:
The kernel component of KVM is included in mainline Linux, as of 2.6.20. The userspace component of KVM is included in mainline QEMU, as of 1.3.
Odd, since in my experience, it’s the most consistently reliable, performant, and easy to setup / use desktop vm package I’ve used. It always seems to “just work” when others don’t
I guess that depends on what we are using it for. I use it for CAD / CAM software that only works in Windows (Vectric Aspire). Nothing else has been able to give me 3d previews with any kind of usable performance.