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More work on finishing up the interface section.

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Tom Alexander
2026-11-01 12:02:13 -05:00
parent b25a01ca61
commit 81d0bc4f7c
1 changed files with 23 additions and 14 deletions
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posts/2026/10/15/qcncm865-mt7927-comparison/index.org
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@@ -23,6 +23,8 @@ This article is at AI level: None. [[https://fizz.buzz/post_ai_levels][Click her
The MT7929 is the clear winner in terms of raw performance (speed / latency) whereas the QCNCM865 used less power. Personally, I am going to stick with the MT7927 because I'm almost always plugged in, so the power usage difference isn't much of a concern, and I find the random latency spikes in the QCNCM865 concerning. If I used my laptop on battery more often, that 1-2 extra watts consumed by the MT7927 could have a meaningful impact on battery life. The MT7929 is the clear winner in terms of raw performance (speed / latency) whereas the QCNCM865 used less power. Personally, I am going to stick with the MT7927 because I'm almost always plugged in, so the power usage difference isn't much of a concern, and I find the random latency spikes in the QCNCM865 concerning. If I used my laptop on battery more often, that 1-2 extra watts consumed by the MT7927 could have a meaningful impact on battery life.
That being said, bluetooth support for the MT7927 is not yet upstreamed, so if you rely on bluetooth, you may want to either use the QCNCM865 or at least wait a bit before adopting the MT7927.
* Comparison * Comparison
** Frequency ** Frequency
@@ -90,26 +92,32 @@ For the signal strength test, I ran src_bash[:exports code]{iw dev wlan0 link} e
[[./files/graphs/signal_strength.svg]] [[./files/graphs/signal_strength.svg]]
** Interface Information ** Bluetooth
The MT7927's bluetooth support has not yet been upstreamed. I added the relevant firmware file but bluetooth still failed to start. The bluetooth works fine on the QCNCM865, so if bluetooth is at all important to you, then you will either want to stick with the QCNCM865, wait a bit before switching to the MT7927, or apply the patches to add bluetooth support for the MT7927 yourself.
** Additional Differences
In addition to measuring the performance of the cards, I also dumped information about the cards by reading from =/sys=, executing =iw list=, and executing =iw reg get=. The differences I found noteworthy are below. In addition to measuring the performance of the cards, I also dumped information about the cards by reading from =/sys=, executing =iw list=, and executing =iw reg get=. The differences I found noteworthy are below.
*** Supported Ciphers *** Supported Ciphers
The MT7927 supports WEP104 and WEP40, whereas the QCNCM865 does not. That being said, those ciphers [[https://en.wikipedia.org/wiki/Wired_Equivalent_Privacy#Weak_security][should not be in use in 2026]]. The MT7927 supports WEP104 and WEP40, whereas the QCNCM865 does not. That being said, those ciphers [[https://en.wikipedia.org/wiki/Wired_Equivalent_Privacy#Weak_security][should not be in use in 2026]], so this difference is inconsequential.
*** Peer to Peer *** Peer to Peer
The MT7927 supports [[https://en.wikipedia.org/wiki/TDLS][T-DLS]] whereas the QCNCM865 supports RSN-IBSS. The MT7927 claims support for [[https://en.wikipedia.org/wiki/TDLS][T-DLS]] whereas the QCNCM865 claims support for RSN-IBSS.
*** Mesh I could not get T-DLS working between two machines both running an MT7927. I had to replace =iwd= with =wpa_supplicant= since =iwd= does not support =T-DLS=. I managed to get the two devices to establish a link, but once that link was established, all traffic between those two devices immediately stopped.
*** Mesh :noexport:
The QCNCM865 supports mesh but the MT7927 does not. The QCNCM865 supports mesh but the MT7927 does not.
*** Beamformer *** Beamformer :noexport:
The QCNCM865 supports SU Beamformer but the MT7927 does not. The QCNCM865 supports SU Beamformer but the MT7927 does not.
*** Spatial Streams *** Spatial Streams :noexport:
The QCNCM865 supports more spatial streams than the MT7927. The QCNCM865 supports more spatial streams than the MT7927.
@@ -119,27 +127,27 @@ The QCNCM865 supports more spatial streams than the MT7927.
| 160 MHz | 1 | 3 | | 160 MHz | 1 | 3 |
| 320 MHz | | 3 | | 320 MHz | | 3 |
*** MU-MIMO *** MU-MIMO :noexport:
The MT7927 supports MU-MIMO whereas the QCNCM865 does not. The MT7927 supports MU-MIMO whereas the QCNCM865 does not.
*** Feedback *** Feedback :noexport:
The MT7927 supports feedback whereas the QCNCM865 does not. The MT7927 supports feedback whereas the QCNCM865 does not.
*** Target Wake Time *** Target Wake Time :noexport:
The QCNCM865 supports Broadcast TWT whereas the MT7927 does not. The QCNCM865 supports Broadcast TWT whereas the MT7927 does not.
*** Longer Than 16HE SIG-B OFDM Symbols *** Longer Than 16HE SIG-B OFDM Symbols :noexport:
The MT7927 supports Longer Than 16HE SIG-B OFDM Symbols but the QCNCM865 does not. The MT7927 supports Longer Than 16HE SIG-B OFDM Symbols but the QCNCM865 does not.
*** Restricted TWP *** Restricted TWP :noexport:
The QCNCM865 supports Restricted TWP but the MT7927 does not. The QCNCM865 supports Restricted TWP but the MT7927 does not.
*** Supported Commands *** Supported Commands :noexport:
The MT7927 supports a few more commands than the QCNCM865. Those commands being: The MT7927 supports a few more commands than the QCNCM865. Those commands being:
@@ -148,11 +156,11 @@ The MT7927 supports a few more commands than the QCNCM865. Those commands being:
- =start_sched_scan= - =start_sched_scan=
- =set_sar_specs= - =set_sar_specs=
*** Software Interface Modes (can always be added) *** Software Interface Modes (can always be added) :noexport:
The MT7927 supports AP/VLAN but the QCNCM865 does not. The MT7927 supports AP/VLAN but the QCNCM865 does not.
*** Other Features *** Other Features :noexport:
**** Only MT7927 **** Only MT7927
@@ -177,6 +185,7 @@ Maximum associated stations in AP mode: 512
[ UNSOL_BCAST_PROBE_RESP ]: unsolicated broadcast probe response [ UNSOL_BCAST_PROBE_RESP ]: unsolicated broadcast probe response
[ BSS_COLOR ]: BSS coloring support [ BSS_COLOR ]: BSS coloring support
[ PUNCT ]: preamble puncturing in AP mode [ PUNCT ]: preamble puncturing in AP mode
* Test Setup * Test Setup
My test setup consisted of a Framework 13 AMD 7040 laptop with each of the wifi cards, connecting to a [[https://techspecs.ui.com/unifi/wifi/u7-pro][Ubiquiti UniFi U7 Pro]]. My test setup consisted of a Framework 13 AMD 7040 laptop with each of the wifi cards, connecting to a [[https://techspecs.ui.com/unifi/wifi/u7-pro][Ubiquiti UniFi U7 Pro]].