The 7.0 graphics have been developed further, and are still in bug-hunt phase.
When you want to try 7.0 again and have problems with 7.0 graphics or seize-ups when 3D is on:
Please upgrade to latest Virtualbox, Extension Pack if used, and Guest Additions.
If this does not get a stable VM, and you have 3D acceleration turned on, try running the VM with 3D acceleration turned off. If that stabilizes the VM, please note that this happened.
Please create a ticket in the
Bugtracker with the problem description, the manufacturer and model of the host PC's graphics card, the graphics driver version (on the host OS), and a (zipped) VBox.log file.
If your host OS is Linux, please provide a zip file with the output of the 'vulkaninfo' command in the Bugtracker ticket, too. (on Debian/Ubuntu/Mint hosts, you may have to install the vulkan-tools package).