My system is a Power Mac 7600 w/ 300mhz G3 card and 288MB ram(fully interleaved) and a IDE to SD card adaptor that maxes out IDE transfers no problem on the Sonnet Tempo UltraIDE ATA66. So in the historical context it should be ok as its pretty high end for the time frame ?
I have tested it with some of my G4 Macs with nVidia ti4600, SSDs connected to a Seriteck 64 bits, 1.5 Gb of RAM and CPUs speeds from 1.5 Ghz onwards.
And even I like its great interface I think it is too slow to be used.
OK it is just my opinion.