The SD card would be under the local tab, but you would have had to install the SD Card yourself.
Lack of SD Card does not explain the pauses on live view and recordings. That is a bandwidth issue somewhere. Either too many video streams being pulled at the same time, bandwidth issue within the NVR, bandwidth issue with the nanostation, too long of an ethernet run, etc.
Do you have substreams on for all of your cameras? Is the NVR and your program to view it on the phone or tablet using the substreams? If you are trying to watch all the cameras at the same time tiled on your screen pulling the mainstream feeds that will do it as well.
Conversely, for kicks, turn substream off on one camera and see if that improves the video stream of that camera- depending on other settings in your camera (too high FPS, etc.), you could be maxing the little CPU out.