R9 290 in xfire + 560 with 13.12 nvidia drivers for physx

because the people at toms hardware are complete and utter arses, I come to a better bunch of people.

Soo my question is can I use 2 R9 290s in xfire + a gtx 560 for physx, also I wanted to know if i could use the GTX 560 to stream to a nvidia shield.

You can but it will required hacked drivers to work together and then it usually doesnt. Minimum requirement for shield streaming is a 650gtx.