I've decided to expand my workstation with a Nvidia Quadro K-series GPU.
In my price range I find the K4000 as well as the K4200
While the K4000 has 3Gb of Ram, the K4200 has 4Gb
Yet, Adobe doesn't list the K4200 card in her list of supported certified cards
While Nvidia claims it works fine and is better then the K4000
So ok, this sounds like an easy choice, but then there's this:
When I search the forums, some say go with the 4200, others tell you to stick with the 4000.
So, Adobe: which one is it?
I work primarily in After Effects: animation, motion graphics, some VFX-work, greenkey stuff, 3D, the usual things I guess.
But which card will give me the better performance?
The price-range is the same, so I's rather go with the one Adobe suggest, than having to take an educated guess out of the 5 million internet posts where 50% say on thing, and the ofther half claims the opposite.
Totally irrelevant. Unless you extensively use Raytrace 3D, none of this matters in any way and even then the usual compatibility issues are probably more critical than the actual minor performance differences. If you have a specific use case/ scenario where one card may have benefits over the other then go ahead and get whatever gets the job done, but otherwise simply save the money and perhaps better invest in some plug-ins that may improve your workflows rather than trying to fix broken features with hardware...
To back up what Mylenium says, GPU (CUDA, OpenGL) features in After Effects
Unless you're using the obsolete ray-traced renderer, the GPU is pretty irrelevant for AE as it comes.
Now, some third-party plugins do make use of the GPU (Red Giant Universe, Video Copilot's Element 3d, Mettle's ShapeShifter, etc.), but their requirements are completely different from AE's ray-tracing ones, so check the system requirements for any third-party plugins you plan to use.