Has anyone tested this scenario? Since PC versions of the 3870 are cheaper than the PC+Mac version, I was wondering if I'd be able to crossfire the PC+Mac version, and a regular PC version. (Obviously I'd only be looking to run Crossfire on the Windows side.) Would this setup cause problems with either the OS X or Windows side? BTW, I've got the 2008 Mac Pro with 2 PCI-E x16 slots. Thanks!