Please find below some diagnoses that may give some clues on the FIFO ACK error,
T-UD2H:~$ sudo ethtool --show-coalesce eth4
Coalesce parameters for eth4:
Adaptive RX: off TX: off
stats-block-usecs: 0
sample-interval: 0
pkt-rate-low: 0
pkt-rate-high: 0
rx-usecs: 20
rx-frames: 5
rx-usecs-irq: 0
rx-frames-irq: 5
tx-usecs: 72
tx-frames: 53
tx-usecs-irq: 0
tx-frames-irq: 5
rx-usecs-low: 0
rx-frame-low: 0
tx-usecs-low: 0
tx-frame-low: 0
rx-usecs-high: 0
rx-frame-high: 0
tx-usecs-high: 0
tx-frame-high: 0
T-UD2H:/etc/network$ sudo ethtool --show-coalesce eth3
Coalesce parameters for eth3:
Adaptive RX: off TX: off
stats-block-usecs: 0
sample-interval: 0
pkt-rate-low: 0
pkt-rate-high: 0
rx-usecs: 20
rx-frames: 5
rx-usecs-irq: 0
rx-frames-irq: 5
tx-usecs: 72
tx-frames: 53
tx-usecs-irq: 0
tx-frames-irq: 5
rx-usecs-low: 0
rx-frame-low: 0
tx-usecs-low: 0
tx-frame-low: 0
rx-usecs-high: 0
rx-frame-high: 0
tx-usecs-high: 0
tx-frame-high: 0
T-UD2H:/etc/network$ ifconfig -a eth4
eth4 Link encap:Ethernet HWaddr REMOVED
inet addr:192.168.10.1 Bcast:192.168.10.255 Mask:255.255.255.0
inet6 addr: REMOVED_by_KE Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:118227 errors:0 dropped:0 overruns:0 frame:0
TX packets:733915 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:8366882 (8.3 MB) TX bytes:930252111 (930.2 MB)
Interrupt:19
GA-MA785GMT-UD2H:/etc/network$ ifconfig -a eth3
eth3 Link encap:Ethernet HWaddr REMOVED
inet addr:192.168.20.1 Bcast:192.168.20.255 Mask:255.255.255.0
inet6 addr: REMOVED_by_KE Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:40807 errors:0 dropped:0 overruns:0 frame:0
TX packets:11811 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:
3100954 (3.1 MB) TX bytes:1076135 (1.0 MB)
Interrupt:18