Video card memory limit on G5s under Linux

Action Retro

Tinkerer
Oct 19, 2021
49
81
18
Hey all, hoping someone has heard of this - I've heard that, under linux, using a video card on a G5 with more than 2gb of memory can cause issues. Does anyone know any details about this?

I recently got one of those JuiceBox external video card power supplies, and I thought it would be fun to experiment with modern-ish PCIE cards on my Quad G5, but finding video cards to tinker with is difficult :)

Thank you!
 

demik

Tinkerer
Oct 11, 2021
42
36
18
It's not limited to GPUs and VRAM. It's related to PCI/AGP Bus or IOMMU. Logic board limitation that macOS has workaround for. Can't remember the detail exactly.

You will have stability issues with PCI Cards, Ethernet and so on with 2 GB+ of RAM as well, same thing with FreeBSD.

I think Quads are immune to it tho, let us know