Hi. CassL.
The good news is you shouldn't need to disable Safe Boot in order to use the GTX 650 Ti. Here's why.
Safe boot is another term for a system called UEFI. What UEFI does (among other things) is to try and prevent certain changes to the startup sequence of your computer - such as the installation of programs called root kits. A side effect of this is that you can't install non-UEFI operating systems on the computer like Windows 7.
Legacy boot is the "normal" (sometimes labeled as fast) boot process. It's used by pre-UEFI operating systems like Windows 7 and is also supported by Windows 8 and Windows 10. It does not have the boot protections of Safe boot, but is far more compatible with older hardware and older versions of Windows.
Unfortunately the two modes are not compatible. The start up process is completely different between the two so if you disable Safe boot on your HP, you will be left with a computer that can't boot into Windows until
you re-install the operating system. Sorry for the bold text, I just wanted to emphasize the implications of what you're trying to do.
If for some reason the GTX 650 Ti doesn't work with the Safe boot (and I can't think of a reason why not) contact the manufacturer of the card for a UEFI firmware update and that should fix the issue.
Hope this helps and happy Simming!
Flynn
We're actually have issues with turning off the secure boot on the Envy Phoenix mentioned above.
After disabling Secure boot and enabling Legacy boot, it's supposed to restart and take you to a page where you enter a code to authorize the change.
We waiting for about ten minutes but the screen never appeared.... So we're at a loss.
Would you happen to know anything about this, since you're good with computers?