Running Tesla K40 in NVENC SDK 5.0 limited to 2 multiple encoding sessions?

When i try to run more than 2 encoding sessions, Error:
NvTranscoder: …/common/src/NvHWEncoder.cpp:447: NVENCSTATUS CNvHWEncoder::NvEncOpenEncodeSessionEx(void*, NV_ENC_DEVICE_TYPE): Assertion `0’ failed.
Anyone have ideas what is going on? NVENC SDK 4,0 have no such issue when running multiple encoding in Tesla k40c

Found the return error from NvEncOpenEncodeSessionEx: NV_ENC_ERR_OUT_OF_MEMORY.
but
nvidia-smi indicates 352MiB out of 11519MiB used only:
Fri Sep 4 15:10:04 2015
±-----------------------------------------------------+
| NVIDIA-SMI 346.59 Driver Version: 346.59 |
|-------------------------------±---------------------±---------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
|===============================+======================+======================|
| 0 NVS 310 Off | 0000:04:00.0 N/A | N/A |
| 30% 65C P0 N/A / N/A | 490MiB / 511MiB | N/A Default |
±------------------------------±---------------------±---------------------+
| 1 Tesla K40c Off | 0000:05:00.0 Off | 0 |
| 28% 58C P0 65W / 235W | 352MiB / 11519MiB | 0% Default |
±------------------------------±---------------------±---------------------+

±----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name Usage |
|=============================================================================|
| 0 C Not Supported |
| 1 5473 C ./NvTranscoder 128MiB |
| 1 5519 C ./NvTranscoder 196MiB |
±----------------------------------------------------------------------------+

Hello, Mr CHANGZHIHAO; ; How many video encode session can you create on TESLA K40 when use NVENC 4.0 ? Because I found 2 session can be create after buy a GEFORCE card; And I want get some performance data with NVENC;

Could you tell me which picture format (width/heigh) you chosen to encode? FPS ? Thank you very much;

Hi,About 13 encoding sessions running with FFMPEG as a decoder.But the CPU usage is very high by using the FFmpeg decoder. SDK 5.0 has lower CPU usage because it combines CUVID & NVENC.The output compression is 1920x1080 res and 25 fps.

Found the problem. NVENC recognised our NVS 310 as a low end GPU.

If the system contains any low end hardware (even in conjunction with other
high end hardware), only two encoding sessions will be permitted

However,we need NVS 310 as VGA output to the monitor. Our server do not have any build in VGA output.
Is there any way to bypass NVS 310 discovery from NVENC?