I finally figured out why PTS failed to install the specviewperf10 test for me
(the installation hangs with ccache).

The proe-04 test only draws the splash screen here, after that I get lines
like:

[drm:radeon_cs_ioctl] *ERROR* Failed to parse relocation -12!

in dmesg, indicating the kernel fails to process the drawing command streams,
probably due to running out of VRAM or GTT memory.

Does that match what you're seeing?