华硕 AX86u 2.5G 网卡速度不正常

我电脑的主板有 2.5G 网卡，但是协商至 2.5G 之后速度不达标，一直保持在 1.2G 左右。

为了排除问题，另购了 2.5G 交换机和 pcie 2.5G 网卡，通过 2.5G PC 给另一台用 pcie 转出来的 2.5G 网口的二奶机排除了自己电脑主板 2.5G 网卡的问题和网线的问题。

贴一下我用 iperf-3 打流量的图

10.0.0.1 是 AX86u 路由器
10.0.0.3 是有 2.5G 网卡的 PC
—————————————————————————————————————————————————————
PS D:\iperf-3> ./iperf3.exe -c 10.0.0.1
Connecting to host 10.0.0.1, port 5201
[ 4] local 10.0.0.3 port 3334 connected to 10.0.0.1 port 5201
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 145 MBytes 1.22 Gbits/sec
[ 4] 1.00-2.00 sec 144 MBytes 1.21 Gbits/sec
[ 4] 2.00-3.00 sec 144 MBytes 1.21 Gbits/sec
[ 4] 3.00-4.00 sec 145 MBytes 1.21 Gbits/sec
[ 4] 4.00-5.00 sec 145 MBytes 1.22 Gbits/sec
[ 4] 5.00-6.00 sec 143 MBytes 1.20 Gbits/sec
[ 4] 6.00-7.00 sec 144 MBytes 1.21 Gbits/sec
[ 4] 7.00-8.00 sec 145 MBytes 1.22 Gbits/sec
[ 4] 8.00-9.00 sec 144 MBytes 1.21 Gbits/sec
[ 4] 9.00-10.00 sec 145 MBytes 1.22 Gbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-10.00 sec 1.41 GBytes 1.21 Gbits/sec sender
[ 4] 0.00-10.00 sec 1.41 GBytes 1.21 Gbits/sec receiver

iperf Done.
PS D:\iperf-3>
—————————————————————————————————————————————————————

To escape to local shell, press 'Ctrl+Alt+]'.

WARNING! The remote SSH server rejected X11 forwarding request.
big@AX86U:/tmp/home/root# iperf3 -s
-----------------------------------------------------------
Server listening on 5201 (test #1)
-----------------------------------------------------------
Accepted connection from 10.0.0.3, port 3333
[ 5] local 10.0.0.1 port 5201 connected to 10.0.0.3 port 3334
[ ID] Interval Transfer Bitrate
[ 5] 0.00-1.00 sec 145 MBytes 1.21 Gbits/sec
[ 5] 1.00-2.00 sec 144 MBytes 1.21 Gbits/sec
[ 5] 2.00-3.00 sec 145 MBytes 1.21 Gbits/sec
[ 5] 3.00-4.00 sec 145 MBytes 1.21 Gbits/sec
[ 5] 4.00-5.00 sec 145 MBytes 1.22 Gbits/sec
[ 5] 5.00-6.00 sec 143 MBytes 1.20 Gbits/sec
[ 5] 6.00-7.00 sec 144 MBytes 1.20 Gbits/sec
[ 5] 7.00-8.00 sec 145 MBytes 1.22 Gbits/sec
[ 5] 8.00-9.00 sec 144 MBytes 1.21 Gbits/sec
[ 5] 9.00-10.00 sec 145 MBytes 1.22 Gbits/sec
[ 5] 10.00-10.00 sec 274 KBytes 1.06 Gbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate
[ 5] 0.00-10.00 sec 1.41 GBytes 1.21 Gbits/sec receiver
-----------------------------------------------------------
Server listening on 5201 (test #2)
-----------------------------------------------------------

如果用 iperf-3 给 127.0.0.1 打流量均能突破 2.5G

致电华硕技术支持得到的答复是：“这是正常现象，我们家的 2.5G 网卡在不作为 wan 口的情况下就是达不到 2.5G 的速度。”

所以是我的使用方法不对呢还是华硕的网卡存在质量问题呢。