I got this adviced as I'm using 256GB of ram, a shitload of raiddisks and using heavy loads of network traffic.
What would be your choice as motherboard ?
Workstation oriented Asus like Z10PE-D16 WS. I am using Z10PE-D8 WS for current build in process as I don't need more than 64gb (but using 16gb sticks you still go up to 192), but D16 has enough to go up to 1024. Looks like it's not easily available outside of OEM builders yet.
Pretty much the same features and usability in workstation environment plus far more comfortable use and better build for performance, minus the server stuff (sas3 ports,...)
But ok, given that you're on rendering forum I had no idea you could use 256gb or prefer to build disk raids inside workstation, so I presume this is more video-editing machine ? No honestly, now I am quite curious :- )
I am not really fond of aggregated links (using multiple NICs on boar), does that really help you with traffic ? I've setup "cheap" 10gbit network (dual-NIC intel cards inside every workstation, plus netgear prosafe unmanaged switch), maybe this is something you can look into given it's probably within your budget ? It's best thing I did since I use SSDs inside file-server, but don't setup any storage inside workstations since I need all three of us in office to access them.
Sorry for side-tracking, I'll still look into what could cause your issue.