I use an i7 MacBook Pro with 8Gb Ram and run P7 in it.

The problem is that P7 does not address all the power functions in the new OS. I suggest going to P9 or PPro newest iteration to address the extra power configurations in the modern Apple systems.

If you don't you will crash.

Lowering some of the render functions in Poser helps me a lot too. You'd be surprised what you can get away with using in a pinch.

I render 1 to 2 low res images to test render the piece in the first launch and to do the final hi res render (300 dpi at 8x10 inches) I relaunce clean or open the file and do a full size render. Usually works fine. Sometimes I will have to reboot the OS if the drive and ram is fragmented and all crash probles disappear.

as far as rendering HOT. When I am at home I render with the AC Power cord attached. If you can use that instead of the battery. It saves battery use for when you really need it to move around and it does run way cooler. I also got the AVIQ angle stand for the laptop which lifts it at a comfortable angle and allows it to run a bit cooler. Any air you can get beneath the base of the computer allowing air flow will help.