- Jul 31, 2012
- HD4600 / RX 570
- Mobile Phone
First, make sure you flashed the latest BIOS for your Optiplex if you haven't done that.I wasn't sure if there was a way I could check before getting into changing it.
It's all in the guide https://www.tonymacx86.com/threads/the-dell-optimac-big-sur-opencore-thread.302383/#post-2165113 you need to boot from the USB into a modified Grub Shell to determine the current setting.
Type this after the prompt (in orange) press return and it will tell you what the offset is currently.
If 0x263 is not 0x2 it's not set to 64MB DVMT. That simple.