So you have a PC with a 10GbE network card connected to a switch with a 10GbE connector, and the switch is also connected (1GbE ports) to ten Deltacast NDI-to-HDMI decoders (DELTA-neo N2H
What do you mean by "external card"?
I suggest drawing a diagram showing the network connections.
Where you write "So problem is on colision between internal and external cards. Or in intel ext 10gbit", are you saying you have two network cards? And if you do have two network cards, are they both connected to a network? The same network - the same switch? Are you asking if NDI might be sending out some data through one card and some data through the other card, and there being network collisions because they are sending at the same time?
You wrote "I have tried it on diferent machine, slower, but good enough, one lan card, onboard, gigabit killer". Do you mean that when using the other machine which is "slower" (less powerful?), the projectors all have steady images? Does that "slower" also mean that Resolume's framerate is less than 60fps? If so, that should mean a lot less NDI data (due to fewer frames to send) and so you are less likely to overwhelm the network.
Try monitoring your Ethernet network send/receive rate. Disable all of your NDI outputs in Advanced Output and add them in one at a time, watching what happens to the data rate (and also observing whether the all the projectors that have their streams enabled have a steady image). Maybe you get to 8 projectors steady, then the 9th is too much.
A single 1080p30 NDI stream is around 120Mbps; if you are getting something like 8 streams before problems, then maybe that says your PC-to-switch connection is only operating at 1Gbps, not 10Gbps (or maybe the greater-than-1Gbps output from the PC is somehow flooding the 1GBe ports).
Maybe you can configure the Deltacast receivers to have fixed IP addresses and isloate traffic on the ports they are connected to on the switch.
Personal note: I haven't used any 10GbE equipment yet, but have been interested in doing essentially exactly what you seem to be trying to do for a few years now, so am very interested to see you solve this problem and report details of what wasn't working and how you do manage to get it to work.