GT 520 as dedicated PhysX

I've a GTX 470 and GT 520 ,I'm only using the GTX as graphics and PhysX.
I thought if I could use the GT 520 as dedicated PhysX and the GTX470 for graphics.
Would this make any deference or ease the load of the GTX 470 so it won't over heat
And how much watts would the GT520 require if I used it as PhysX

Probably see little to no gain from using such a low end card for Physx. From looking around I can't find anyone that recommended using a GT 520 for Physx, with most recommending at least a GT 550 Ti,

Physx GPU considerations - Guru3D.com Forums

As far as power requirements for that card, unless you're already close with what you have I wouldn't worry about it. That card only uses around 39W at peak load,

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