I would think it would require more GPU power than CPU. Unless you're using AutoDesk products that in general take way too many resources, CPU and GPU.
I'd suggest going to the software site and see if the new specs are good enough
In those apps hyperthreading helps, but it's not that big of a performance increase. Perhaps 10% performance increase for a lot more money. In a device like the surface pro, that shouldn't be a deal breaker. Just being able to run that workload on a tablet form factor device is amazing and surface pro 2 should run it pretty well even without the i7. If you make a living working in those kind of apps then I think a surface pro 2 should probably supplement a very powerful desktop.