Loss of image synchronicity when using 2 GPUs

[Mr_terkin]

Hello. I have 2 qadro rtx 5000 and qadro cync 2 cards in my system. For test I use an image output on an LED screen that is connected by 4 video outputs. There are two outputs in one qadro 5000 and two in the second qadro 5000. The resolution and frequency of the outputs are the same, and the nvidia control panel has enabled syncharnization for these four displays, but a desynchronization is visible at the junction. Tell me how to fix it without using a mosaic.

For the test, I used a 2.6 screen and different processors/cards (660/vx1000 (by pass)/mctrl 4k. it says in the Nvidia control panel that there is synchronization, sometimes you can even see it when outputting content, but it regularly falls apart, the drivers on the video card are the latest and the current version of the algorithm. The mosaic option is not suitable because we have only 2 GPUs and it is planned to use 7 outputs to a single LCD screen and 8 for the control monitor in the maximum set. We managed to achieve synchronization a couple of times with the output of one footage, but as soon as we activate the capture layers and ndi, the synchronization crumbles. Tell me who worked on a system with 2 GPUs and a qadro sink II, what are we doing wrong and why stable synchronization cannot be achieved.

[Anothertom]

When you see loss of synchronisation, does nvidia control panel still show them being synchronised? In system topology does it show as active and in use or as available? Are you using the same signal flow for all outputs, not mixing processors on different parts of LED? Are you feeding a genlock signal to your LED processors and the Quadro Sync card?

If you test with monitors rather than the LED, does the behaviour change?

[Mr_terkin]

When synchronization is lost, Nvidia control indicates that synchronization is present. In the tests, the diode and processors are all used the same, the endpoints and resolutions of the processors are the same. We do not use an external genlock, we use only the software one that is available in quadro sink II, we make one of the outputs a server and the others a client. They also added the genlock via USB for the vx1000, with the genlock on and off on the quadro sink II, but it didn't work.

It makes no sense to conduct a test with monitors, because due to the frames, the out-of-sync in the picture will not be visible.