[問] iPerf3 內網網路速度比外網慢?

今天我好奇一下，去看看我內網速度是多少
我本身對外網路是40Mbps / 5Mbps
都可以跑滿

但是我在我PC (可測得外網全速) 以及一台 Asus 筆電 (也可測得全速) 設置 iPerf
PC為客戶端，筆電為伺服端
指令為 iperf3.exe -c 192.168.0.108

結果跑出來只有26Mbps!
難怪我 IIS 上面有影片看了都會卡._.

兩個都是用 WiFi 5Ghz Bandwidth 20Mhz (怕掉封包), Channel 44
都離 Router 只有 2 公尺
Router: Tp-link AC750 v1 EU (刷US 繁體版韌體)

PC WiFi: T2U
Asus WiFi: QC9337 (?)

請問問題所在呢?
20Mhz 也不至於只有26Mbps吧? 外網比內網快...
或者是 Router CPU 太爛?

Server: 筆電

Connecting to host 192.168.0.108, port 5201 [ 4] local 192.168.0.106 port 51341 connected to 192.168.0.108 port 5201 [ ID] Interval Transfer Bandwidth [ 4] 0.00-1.00 sec 3.25 MBytes 27.3 Mbits/sec [ 4] 1.00-2.00 sec 3.12 MBytes 26.2 Mbits/sec [ 4] 2.00-3.00 sec 3.12 MBytes 26.2 Mbits/sec [ 4] 3.00-4.00 sec 3.00 MBytes 25.2 Mbits/sec [ 4] 4.00-5.00 sec 3.12 MBytes 26.2 Mbits/sec [ 4] 5.00-6.00 sec 3.12 MBytes 26.2 Mbits/sec [ 4] 6.00-7.00 sec 3.00 MBytes 25.2 Mbits/sec [ 4] 7.00-8.00 sec 3.00 MBytes 25.2 Mbits/sec [ 4] 8.00-9.00 sec 3.00 MBytes 25.1 Mbits/sec [ 4] 9.00-10.00 sec 3.00 MBytes 25.2 Mbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth [ 4] 0.00-10.00 sec 30.8 MBytes 25.8 Mbits/sec sender [ 4] 0.00-10.00 sec 30.7 MBytes 25.8 Mbits/sec receiver iperf Done.

Server: 桌機

----------------------------------------------------------- Server listening on 5201 ----------------------------------------------------------- Accepted connection from 192.168.0.108, port 13240 [ 5] local 192.168.0.106 port 5201 connected to 192.168.0.108 port 13241 [ ID] Interval Transfer Bandwidth [ 5] 0.00-1.00 sec 2.75 MBytes 23.0 Mbits/sec [ 5] 1.00-2.00 sec 3.18 MBytes 26.7 Mbits/sec [ 5] 2.00-3.00 sec 3.15 MBytes 26.5 Mbits/sec [ 5] 3.00-4.00 sec 3.14 MBytes 26.4 Mbits/sec [ 5] 4.00-5.00 sec 3.19 MBytes 26.8 Mbits/sec [ 5] 5.00-6.00 sec 3.17 MBytes 26.6 Mbits/sec [ 5] 6.00-7.00 sec 3.04 MBytes 25.5 Mbits/sec [ 5] 7.00-8.00 sec 3.16 MBytes 26.5 Mbits/sec [ 5] 8.00-9.00 sec 3.09 MBytes 26.0 Mbits/sec [ 5] 9.00-10.00 sec 3.04 MBytes 25.5 Mbits/sec [ 5] 10.00-10.08 sec 290 KBytes 30.3 Mbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth [ 5] 0.00-10.08 sec 0.00 Bytes 0.00 bits/sec sender [ 5] 0.00-10.08 sec 31.2 MBytes 26.0 Mbits/sec receiver

桌機 speedtest.net:



Router 設定:



沒有設 AC 是因為會掉包很嚴重._.

網路設定畫面:



對外都可以跑滿了，內網至少也要50M 吧._.
到底是哪裡出錯了呢?
本人沒有要求太多，只要內網可以跑得比外網快就好...
(btw 測外網速度沒用iPerf 是因為 Asia 好像沒什麼 iPerf 伺服器... speedtest-cli 要 linux, 我 linux 電腦壞掉._.)

以下兩台電腦配備:
Asus s410:
CPU: i5-8250u
GPU: MX150
WiFi: QC9337
RAM: DDR4 4G x 2 2400Mhz
SSD: C:240G D:480G (A400)

Asus un62v:
CPU: i7-4600u
WiFi: T2U
RAM: DDR3 4G x 2 1600Mhz
SSD: C: 240G