I ran Xbench... will run the benchmark you posted tomorrow, but here are the results of Xbench- (the program unexpectedly quit after the last test in the first screenshot... in the second shot, it finished the memory test and just started the disk test, which has been running for a while)
Edit: I tried the benchmark in the link above, but it appears the archive is corrupt. I tried downloading it in Windows and copying it to the emulator, and I tried downloading and extracting it right inside Basilisk II, gave the same error both times, so I think it's a link to a bad file.