Hi there

Personally I would invest money to better GPU,with GPU I can render lot faster than with any CPU available at moment in SuperFly,but this depends on scene etc but I do sometimes very large scenes with several props and several figures and I still didn't have issue with VRAM,my current GPUs are GTX1080Ti with two GTX1080 and rendering is really fast,I didn't tried to do animation and due this I can't comment

Getting older Xeons is good way how to get some performance but you need to understand,LGA1366 or X58 is old architecture and going back to X58 from yours 6 core/12 thread CPU will be downgrade or sidegrade in most,in C4D Benchmark dual Xeon 12 core/24 thread X5690 will score same as my i7-5960x with 4.3GHz OC which is 8 core/16 threads and ThreadRipper 16core/32 thread will demolish like my and dual Xeon setup in rendering,my current CPU will score in CineBench around 1600CB and ThreadRipper scores around 3000CB or 3300CB with 4.0GHz OC

Older generation of CPU have different IPC and due with every new architecture like is Haswell etc yours IPC is better and better,Cinebench and few others renderers scale pretty good with every arch etc

Good benchmark is Corona Renderer or CineBench which are most used renderers with V-RAY,there are benchmarks with all of these renderers where you can test yours CPU if its really slow or fast etc

At moment I'm still on X99 but I will be switching to X399 or ThreadRipper just I'm waiting on EK waterblock to be released or something along these lines,these chips can run hot when are OC and I'm looking get that CPU OC

Rendering with GPU and animations you need to understand,previous generation of GPU like has been Titan X or GTX980Ti they're been awesome GPU,but with Pascal rendering in SuperFly is lot faster in my case,I've owned GTX Titan X with GTX1080 that time and switching from GTX Titan X to another GTX 1080 my render speeds has been lot faster than with Titan X and GTX1080,right now have 3x GPUs and rendering is pretty fast,I usually render up to 45 samples for quick renders but usually I end up with 100 samples,Cycles or SuperFly never been optimized for Maxwell GPUs(GTX9xx and Titan X) and due this we are never seen fast render speeds with Maxwell GPUs

Due this I would be vary or careful with choosing next path there,AMD is planning to release their Radeon Pro SSG which should have on board 16GB VRAM and can use SSD up to 2TB as cache disk and in theory you can fit up to 2TB worth of assets in GPU which should be enough for most of the renders I think,just we need to ask SM about the supporting OpenCL and we can use AMD GPU for rendering,if we will be locked in Nvidia environment then we are screwed,same has been with Intel until AMD showed their CPU with affordable prices,Intel would charge us or give incremental upgrades with every arch

if you are on X99 then other option is get Xeon there,I've run 14 core/28 thread E5-2683v3 which has been awesome rendering CPU although if you do use SW which do use only single core you will be struggling but still has been better than my old X5670 with 4.2GHz

Hope this helps

Thanks,Jura