That's fine, and it fits your budget well.
i know autocad works fastest on single thread performance but this computer will be used for a wide range of applications. so a mix of single thread and multi thread performance works for me.
Right, but that's 2 more threads, 1 more FPU, more power to handle, and you won't make much, if any, use of those added threads. By increasing your budget for an FX-8350, you could afford an i5, and a cheaper i5 than the FX-8350 would still be faster for 99% of what you'll do. The FX-6300 makes sense, and will offer you good multitasking and gaming bang/buck. Past the FX-6350, it would not make sense to stay with AMD. With a fairly limited budget, it makes a lot more sense, IMO, to put more money into the GPU, unless your main focus is MMOs.
If your productivity software will mostly be for architectural use, landscape, or civil engineering, RAM capacity and GPU drivers will be the only limiting factors worth worrying about, with all but the lowest-end CPUs available. Quadros and FirePros cost a lot more, for a bit of interface smoothness, so are not worth it for a budget box that also needs to handle gaming, so that one you just accept. For school courses, as well, keep in mind that the course work will need to be possible to work on with 2+ year old cheap notebooks, much less a current budget gaming box, so I really don't think you have anything to worry about, there.