[SOLVED] AX201 Slow WiFi

raywhiteside · ‎05-14-2021

I am running arch linux on a thinkpad x1 carbon gen 9 which has an AX201 wireless card, I'm getting 50-100 Mbps on wifi to a wired LAN target and expect to get 2-4x that. My phone in the same location can max out my internet connection at 200 Mbps down to an external target.

❯ dmesg | grep iwlwifi
[    3.731455] iwlwifi 0000:00:14.3: enabling device (0000 -> 0002)
[    3.735538] iwlwifi 0000:00:14.3: api flags index 2 larger than supported by driver
[    3.735550] iwlwifi 0000:00:14.3: TLV_FW_FSEQ_VERSION: FSEQ Version: 89.3.35.37
[    3.735788] iwlwifi 0000:00:14.3: loaded firmware version 62.49eeb572.0 QuZ-a0-hr-b0-62.ucode op_mode iwlmvm
[    3.886827] iwlwifi 0000:00:14.3: Detected Intel(R) Wi-Fi 6 AX201 160MHz, REV=0x354
[    4.074868] iwlwifi 0000:00:14.3: base HW address: 80:45:dd:32:86:a1
[    4.090683] Modules linked in: snd_soc_hdac_hda pcc_cpufreq(-) kvm(+) snd_hda_ext_core acpi_cpufreq(-) snd_soc_acpi_intel_match snd_soc_acpi soundwire_bus irqbypass crct10dif_pclmul crc32_pclmul aesni_intel snd_soc_core crypto_simd intel_cstate snd_compress intel_uncore iwlmvm ac97_bus ghash_generic gf128mul snd_pcm_dmaengine ghash_clmulni_intel cryptd snd_hda_intel gcm snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec ccm mac80211 psmouse pcspkr snd_hda_core algif_aead snd_hwdep snd_pcm des_generic libdes libarc4 i2c_i801 snd_timer i2c_smbus iwlwifi cbc ecb algif_skcipher mei_me mei cfg80211 cmac md4 intel_lpss_pci intel_lpss idma64 algif_hash intel_ish_ipc(+) af_alg processor_thermal_device intel_ishtp processor_thermal_rfim processor_thermal_mbox processor_thermal_rapl intel_rapl_common thunderbolt tpm_crb intel_pmt intel_soc_dts_iosf tpm_tis tpm_tis_core ucsi_acpi tpm typec_ucsi typec rng_core roles wmi i2c_hid_acpi i2c_hid thinkpad_acpi platform_profile ledtrig_audio rfkill snd

❯ iw wlan0 link
Connected to d2:40:d0:55:c1:f2 (on wlan0)
	SSID: method_one_clinic
	freq: 2422
	RX: 422869873 bytes (47961544 packets)
	TX: 958854568 bytes (5749423 packets)
	signal: -47 dBm
	rx bitrate: 144.4 MBit/s MCS 15 short GI
	tx bitrate: 144.4 MBit/s MCS 15 short GI

	bss flags:	short-preamble short-slot-time
	dtim period:	4
	beacon int:	200

❯ iperf -c laptop --dualtest
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size:  128 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to laptop, TCP port 5001
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  5] local 192.168.1.desktop port 38286 connected with 192.168.1.laptop port 5001
[  4] local 192.168.1.desktop port 5001 connected with 192.168.1.laptop port 59566
[ ID] Interval       Transfer     Bandwidth
[  5]  0.0-10.1 sec  22.6 MBytes  18.8 Mbits/sec
[  4]  0.0-10.4 sec  82.1 MBytes  66.5 Mbits/sec

raywhiteside · ‎05-14-2021

Solution here:

https://www.reddit.com/r/archlinux/comments/nc8o49/slow_wifi/gy5ea9s/?utm_source=reddit&utm_medium=web2x&context=3

On my router I deselected "Enable 20/40 MHz Coexistance". Now I get 230 Mbps down via Speedtest and 350-400 Mbps on LAN to a wired target.

DeividA_Intel · ‎05-17-2021

Hello raywhiteside,

I would like to thank you so much for your input, this will help us and the community a lot. Keep sharing your discoveries with us.

Regards,

Deivid A.

Intel Customer Support Technician