Another Thought I Left Out. On any amount of cores, whether 16 cores on one processor or 4 processors with 16 cores each = 64 cores Total,,, I know Windows 8 64-bit for sure will utilize 100% of each core across all 64 cores. And you will still be able to work! But keep in mind it's only applicable to the programs that are multi-threaded and 3D Studio Max and various others, they will use all resources. (Not entirely sure on Vray)
I have run stress tests on my two 4-core processors (AMD Opteron 2378 Shanghai 2.4 GHz) (on a Server SuperMicro Motherboard) with Maya Rendering and running anything and everything I could imagine, and my system didn't blink, or miss a beat. Considering I have 8GB ECC Registered Ram, though not a lot, but quite adequate to run everything I had possible to test simultaneous. You will have your limitations on graphics modeling work while rendering depending on your card. (I recommend minimum 1 GB Ram memory per core, but you will benefit if you can increase that.)
Make sure you are running Windows 8 !!64-Bit Operating System ESSENTIAL!, Not 32-bit Operation System. These are 64-bit processors and to make Full use of them properly, you need 64-bit OS. Don't have it? Upgrade. It will cost you same as a stick of memory or two.
Windows 8 64-bit shows you in Task Manager, under Performance tab,,,click CPUand shows exactly your processor. Mine reads: "Quad-Core AMD Opteron(tm) Processor 2378" ,,, and underneath shows your CPU Utilization Percentage Graphs. 1 Graph Per Core. Below that, it will display real time Utilization %, Speed (typically locked)2.4GHz on mine, Processes, Threads, Handles and Up Time. Next to that it has Maximum speed: 2.40 Gz, Sockets:2 Cores: 8, Logical Processors: 8, Virtualization: Enabled, L1 cache:1.0 MB, L2 cache: 4.0 MB, L3 cache: 12.0 MB
So you can see Windows 8, 64-bit gives you a little more insight as to your computer components and how it's being used realtime. I understand the 32-bit version won't show a performance utilization box graph for each core like Windows 8 does.
I hope that helps you.