8.6 would be why the difference. The higher the system the more resources it uses. I would suggest a true comparison would be to have an external scsi drive to boot from and boot the 6100 into the same OS and I'm sure it will run circles around the 7200 board. Mine does. I bought a G3 card for my 7200 straight from sonnet and they sent me an A series board and their website says the A series doesn't work. Kinda crappy huh.