Glorfendel

There could be one of a few things going on here. 
 
1. The teaming protocol being used. Switch independent (default on windows 2012) is mostly for redundancy switch independent is fast out slow in. this is due to the switch trying to prevent a switching loop\storm buy sending data from 1 session to multiple places. 
 
2. Spanning tree even if it’s not a smart switch it’s not a hub it is going to do some mid-level network tech and protocols. Setting a team on a switch (depending on brand) will disable STP on those ports. 
 
3. The switch has Green mode or some other such bullshit. Power saving modes tend to cause problems with all advanced network protocols 
 
4. Security crap some switches now are including SPI this will destroy any and all teaming and multi-channel services. 
 
5. Switch backplane splitting this if very much a problem with low end switches a 12 port switch only has the hardware to run 8 at max speed and or its just 3 4 port switches glued together the only fix is get a new switch.
 
I believe Linus is using a netgear XS these support LACP it’s an l2 plus switch it has some manageability.  Note client versions of windows can’t team natively. 
 
sigh as someone that does this for a living ( San Storage for virtualization and the media industry ) using a cheap switch when teaming or trying to get anywhere near the max of the standard is not going to happen. Buying a cheap switch and attaching high end high speed gear to it is like buying a no name power supply. Sorry rant off 

I would be concerned with the drives moving around a lot of 4k video the TBW on the drives is not that great. To be honest the TBW on even Intel and Samsung Enterprise drives is not that great. Are your plans going to be to do push\pull or work directly over the network? with raid you get burned extra on wrights for parity so the problem becomes even more compounded the wright parity cost on that raid is plus 60% you will find your self replacing drives quite often.  Does anyone know what Kingston drives do when they cross the TBW do they go read only die or keep going? Most enterprise drives will read only or the MTTF\MTBF will go off. 
 
 
 
 
The Cache on the raid cards, the battery's he really needs, multi point read, drive monitoring ( MTTF) etc. raid is going to offer better performance and less chance of a major failure over ZFS.