for ease I disconnected the r606 and I am only testing the gekko hub with the newpacs (I also tried with the terminus running and I am getting the same results)
also for ease every time I am running a NP the frequency is set to 100 (always with cooling)
all usb on the mobo have been tried with same results (btw the terminus runs the same on all usb 2.0 and 3.0)
all ports on the gekko have been tested (except the "D" port)
all newpacs have been tested one by one (all plugged into the hub and also just connected one at the time to the gekko)
If all that continues to create the same issues. Your next method would be to use the front ports. Since this is not in a case you will need to find a way to plug a usb header cable into one of the usb header ports on the MB. As you currently have 2 for usb 2.0 and 2 for usb 3.0...
I only had access to some 2.0 front ports to test, same result
I bought some 3.0 front ports I should get in a couple of days and I will update you on that
Last option, pick up a raspberry pi 4, throw them into a closet and call it a day

I might be able to have a friend lend me one .. not sure if he still has it but it'd be nice to run them on it for sure and see what happens !!!
If it behaves the same even with an R606 plugged in, it's not a USB throughput limitation because bandwidth use is directly proportional to total hashrate. Does it matter how ports are used on the hub?
I didn't know about that (very curious) but while I was playing with the NP here is how I tried to dissect the all thing
I am using serial numbers for targeting, now that all ports have been tested I am using ports 3, 4, 6 and 7 on the gekko
the setup:
https://imgur.com/hYJGrILtest 1: run 808 and 838 on one 6A lane =
https://imgur.com/fyiHDyj OK
test 2: run 839 and 836 on one 6A lane =
https://imgur.com/PK1T6Db OK
test 3: run 808 and 836 on two 6A lane =
https://imgur.com/1EYJlxB OK
test 4: run 838 and 839 on two 6A lane =
https://imgur.com/zJ26RJf OK
test 5: run all of them with one instance for each 6A lane = boom problem
https://imgur.com/yOs36ZOsame thing if I just run one instance for all the NP https://imgur.com/XA5GE3o
All ports on the hub were tested?
absolutely yes, 1 through 7, one by one, except for the "D" port on the 2A lane
Back six from the power input are powered for the sticks right?
not sure what you mean here, the hub is powered by the psu if that's what you are asking
EDIT: here is all four of them running at freq 200 for less than an hour:
https://imgur.com/LiBPXdcEDIT 2: what is the red light on the gekko hub ?
https://imgur.com/X9pPZ0kI was running 838 and 836 in ports 3 and 6 and it was off. I plugged 808 and 839 in 4 and 7 and now it's on ..