I'm an engineer for an Audio Video Integration Company. I use autocad on a daily basis. Will the gts 450 work well for 3d modeling. I also do mid-range gaming, photo/video editing, and internet. Any opinions.
As long as you have a beefy CPU and enough RAM available, it will work just fine.
With most CAD software, a high powered GPU is not really necessary (unless you are working with excessively complex parts/assemblies).
For gaming, a GTS 450 should give you enough power for gaming at mid resolutions, possibly requiring lowered settings in some games.