Take 1 Mac pro.
Take 1 Atto ExpressSAS H380 PCIe card.
Observe that it works fine in OSX.
Install Windows using Bootcamp.
Observe that it breaks horribly, even failing its POST health checks.
Check it works great in OSX again.
Find real computer with proper BIOS and actual working PCIe slots.
Check that SAS card works great, whatever OS you put on it.
Kick Mac Pro.
Throw Mac Pro away.
Conclusion: Macs suck. Maybe not for everyone, but for the things I want to do with them, they suck.