@koberulz:
When you copy and paste the various Event Viewer errors etc. are you editing out any information? If so, do not do so, At most mask out the last few letters of the computer or server name if you believe that those names could be personally identifying.
The reason for screenshots is to ensure that what is being done is 1) applicable to the the overall described network environment, and 2) correct for that environment. Typo's are notoriously hard to notice sometimes.
As for the NAS static IP addresses, they can be as you chose provided that the chosen static IP's are outside of the DHCP IP address range allowed to the router and that each assigned NAS static IP address is reserved for the NAS via the respective NAS's MAC. I would use 192.168.0.2 (already in use - ok) and 192.168.0.3 (if not in use) for the second NAS. Makes the NAS IP addresses easy to find and/or identify when problems occur.
Key is to have some consistent IP addressing scheme in use with respect to the use of DHCP and Static IP addresses.
I use a scheme that allows me to recognize what a device may be: major network component, shared, wired, wireless. Apple "i" device, camera, misc (electrical system monitor), guest.
You really need to have an overall network diagam that shows all network devices, their connectivity, IP addresses (DHCP/Static), MAC's etc.. And then use "ipconfig /all", "arp -a" etc. to confirm that all is correct. And also look in the router's admin screens/menus or device lists to ensure that all is consistent - no duplicates.
That all said, at this point I believe that
@lantis3 is narrowing this all down. My suggestion is to order the other NIC, wait the week+ (if necessary), and then proceed as posted.
Indeed the problem may be related to "Killer's" long history of issues. However, that is likely being complicated by misconfigurations and/or other errors and problems with respect to network devices.
The problem is in your network and all we can do is to try to help by guiding and suggesting. You must be much more proactive on your end with respect to trying to resolve the issues at hand. And that can be quite frustrating - no easy answers sometimes.
If you do not understand something then start googling and reading. E.g., how to disable or uninstall a device driver. Check end user documentation via the applicable manufacturer's websites.