Herve, thanks for the quick reply, I guess I'll go for El Capitan then! And thanks for the tip on the wireless!
Any other tips?
Are people able to get HDMI out and DisplayPort working?
My wife asked why I'd do this, and I said because I can, (and upgrading from XP to Win7 or 10 - would be almost as much of a pain with hunting down drivers).
I'll try to take good notes and post for the E6500.