Single gtx970M but desktop i7-4790k or dual gtx970M but laptop i7-4810MQ

Before I pull the trigger on which one I'm going to buy I'd like to ask your opinions on wether it's worth paying the extra price for the SLI, if that means I'll have to go with a worse processor.

The two specific laptops I'm talking about are the xmg U705 and the xmg P724.

The laptop will be used for rendering (both video rendering and 3d rendering), aswell as coding and heavy multitasking, so I will need both.

There's also a difference in the ports they have.
The U705 supports up to 3...

Single gtx970M but desktop i7-4790k or dual gtx970M but laptop i7-4810MQ

Single gtx970M but desktop i7-4790k or dual gtx970M but laptop i7-4810MQ