You'll probably be fine without it, but I have not tried any Daphne games so far with mine.
I wanted to run MAME with HLSL on, but had a few issues with lag. I also wanted to run the Dolphin emulator, which worked, but the framerate was terrible. After the gfx card upgrade, everything seems to be running great. I did have a bit of framerate stutter w/ Naomi, but I haven't tweaked the settings much on that yet.