Hello All,
I have a Mac Pro 2008 with an ATI Radeon HD 5870 installed into PCI slot 1. I also have DosDude's Patched Mac OS Catalina on this machine. The current display I am using is an Apple Cinema HD Display Aluminium 23-inch (1920 x 1200). i wanted to have a Dual Display setup, so I pulled out my old ViewSonic LCD monitor. I connected said monitor via a VGA cable and a Mini DisplayPort to VGA Dongle. However, The computer doesn't detect the ViewSonic Monitor. I have tested the ViewSonic monitor, the Vga cable, and the Dongle. all three peripherals are funcitional. I don't know what's going on. If anyone knows, please commnet
I don't know about that card specifically, but it may be that it doesn't pass a VGA signal, in which case you'd need an active VGA adapter.