http://www.vintagemacworld.com/radius/thuniv.html
"Q: Why does my Thunder IV GX card fail the Apple diagnostics hardware test program?
A: This program is not designed for testing any products other than those manufactured by Apple, therefore it will always report that the VRAM is defective on your card. This test always fails on third party graphics cards even if the card is working perfectly. If there really was a VRAM problem with your card, you would see some visible sign of the problem on the screen. VRAM failures generally result in one or more vertical lines of garbage or distortion being displayed on the screen. If you reduce the resolution of the image or reduce the bit depth from 24-bit to 8-bit and see some change to these lines, the VRAM probably is defective and the board should be replaced. If you don't see any problems with vertical lines on the screen in any bit depth or resolution, then your card is working correctly."
You seem to have the latest ROM installed, the T cycles resolution so the card is functional, I didn't see the DSP card attached which would have issues if VM was enabled, not much else I can say.
"Q: Why does my Thunder IV GX card fail the Apple diagnostics hardware test program?
A: This program is not designed for testing any products other than those manufactured by Apple, therefore it will always report that the VRAM is defective on your card. This test always fails on third party graphics cards even if the card is working perfectly. If there really was a VRAM problem with your card, you would see some visible sign of the problem on the screen. VRAM failures generally result in one or more vertical lines of garbage or distortion being displayed on the screen. If you reduce the resolution of the image or reduce the bit depth from 24-bit to 8-bit and see some change to these lines, the VRAM probably is defective and the board should be replaced. If you don't see any problems with vertical lines on the screen in any bit depth or resolution, then your card is working correctly."
You seem to have the latest ROM installed, the T cycles resolution so the card is functional, I didn't see the DSP card attached which would have issues if VM was enabled, not much else I can say.