Which type of card can support more than 2 nvencsdk encode sessions simultaneously?

The “NVENC_DA-06209-001_v06.pdf” in NVENCSDK 5.0 said:

“The current SDK package allows up to two simultaneous encode sessions per system for low-end Quadro and GeForce cards. If the system contains any low-end hardware (even in conjunction with other high-end hardware), only two encoding sessions will be permitted.”

I test the nvencoder in my Gefore GTX970 card,it only allow me create 2 encode sessions,but my app need more encode sessions than two,so which type of card should I use? what’s the max number of concurrent encode sessions I can create?

I have encountered this problem too.
thd “NVENC_DA-06209-001_v08.pdf” documentation mentioned the application can run N simultaneous encode sessions on Quadro K4000 card (where N is
defined by the encoder/memory/hardware limitations)
If I had A Quadra M4000 8G GDDR5 card, How to calculate the “N”?