I'm curious if any BIOS settings were changed following the update and you had not set them as before.
I'm wondering if on some systems, having HPET enabled in the BIOS results in instability. I had disabled it in BIOS, and re-installed the beta AMD driver (clean install, following uninstall in safemode with DDU) after having installed over the previous driver version.
I was in a rush and didn't care about troubleshooting procedure/documentation of efforts, as I usually am with my own personal system, and turns out one of those changes resulting in resolving my game crashes.
I'll check today but its all defaults, only the serial port is disabled and MCE is enabled so I run all cores of this 5930K @ 3.7GHz. The BIOS notes improved PCI-E and DRAM compatibility. HPET is probably enabled.
On performance I think I'll use Rockstar's softest shadows and up grass to Very High. Both PCSS and CHS whack performance according to HardOCP preliminaries (and they may not even look as good). See the FPS then.