Dynamic lights not working because of video card?

I've read online that ATI cards might have trouble rendering dynamic lights with Z/GZDoom, which is the case for me, as my PC has an old ATI card. Should I just get a new one, which I'm planning to eventually do, or is there a workaround? Lights.pk3 has no effect on things and I have dnyamic lights turned on in the executable.

GZDoom 2.x is more demanding when dynamic lights are concerned. Have you tried 1.x?

The current devbuilds may have problems with dynamic lights and older graphics cards because I am currently working on that.

I had to disable a few features on old ATIs due to some broken drivers with insufficient support for some required features and the workaround is not ready yet.