AC68U 2.4GHZ slow and poor latency

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garce
DD-WRT User


Joined: 24 Aug 2016
Posts: 56

PostPosted: Mon Feb 06, 2017 4:39    Post subject: AC68U 2.4GHZ slow and poor latency Reply with quote
Hi,
I have AC68U with Firmware: DD-WRT v3.0-r31205M kongac (02/03/17)
I am having issues with 2.4GHz performance
2.4GHz speed is 12mbps and latency > 80 ms
5GHz speed is 28mbps and latency is ~35ms
My ISP is 30mbps

This happens across computers.
Regulatory Domain: United States
Regulatory Mode: Off
TPC Mitigation Factor: OFF

Wireless Physical Interface wl0 [2.4 GHz TurboQAM]

Physical Interface wl0 -
Wireless Mode: AP
Wireless Network Mode: Mixed
Wireless Network Name (SSID): ABC
Wireless Channel: 6
Channel Width: 20MHZ
Wireless SSID Broadcast: Enable
Optimize Multicast Traffic: Enable
TurboQAM (QAM256) support:Enable
Explicit Beamforming: Enable
Implicit Beamforming: Enable
Airtime Fairness: Disable
Network Configuration: Bridged

Wireless Physical Interface wl1 [5 GHz/802.11ac]


Wireless Mode: AP
Wireless Network Mode: Mixed
Wireless Network Name (SSID): ABC5
Wireless Channel: 48
Channel Width: VTH80
Extension Channel: upper upper
Wireless SSID Broadcast: Enable
Optimize Multicast Traffic: Enable
Explicit Beamforming: Enable
Implicit Beamforming: Enable
Airtime Fairness: Disable
Network Configuration: Bridged

Both have WPA2 Personal with AES for security

Any advice is appreciated. Thanks!
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leadboots5
DD-WRT User


Joined: 05 Feb 2010
Posts: 83

PostPosted: Mon Feb 06, 2017 5:55    Post subject: Reply with quote
What speed to get wired?
Have you enabled any other features?VPN/QoS etc..
Did you clean nvram after flashing to ddwrt?

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Linksys E3000
ASUS RT-AC68U
garce
DD-WRT User


Joined: 24 Aug 2016
Posts: 56

PostPosted: Mon Feb 06, 2017 12:38    Post subject: Reply with quote
leadboots5 wrote:
What speed to get wired?
Have you enabled any other features?VPN/QoS etc..
Did you clean nvram after flashing to ddwrt?

Wired is more less same as 5GHz (constrained by isp download speed)
I dont have any settings for VPN/QOS, etc
I cleared nvram after I reflashed the original TMO firmware and move to ASUS firmware. Afterwards I upgraded to dd-wrt and now on kong. I only cleared nvram as part of process of removing TMO firmware.
I dont want to lose all my settings (several access restrictions policies at home)
mgw2011
DD-WRT User


Joined: 24 Sep 2011
Posts: 61

PostPosted: Mon Feb 06, 2017 14:09    Post subject: Reply with quote
What are you running on the client side?
garce
DD-WRT User


Joined: 24 Aug 2016
Posts: 56

PostPosted: Mon Feb 06, 2017 14:16    Post subject: Reply with quote
Windows 10 in several machines.
The strange part is that if I switch to 5GHz it works much better.
One thing, I did created a guest network on 2.4GHz and later deleted it since I thought it was causing some of the "occasional wifi lost" and also at some point several 2.4GHz stopped working
mgw2011
DD-WRT User


Joined: 24 Sep 2011
Posts: 61

PostPosted: Mon Feb 06, 2017 17:35    Post subject: Reply with quote
garce wrote:
Windows 10 in several machines.
The strange part is that if I switch to 5GHz it works much better.
One thing, I did created a guest network on 2.4GHz and later deleted it since I thought it was causing some of the "occasional wifi lost" and also at some point several 2.4GHz stopped working

Why not stay with the 5GHz then?

2.4 GHz is usually pretty crowded ... did you check for neighborhood WLAN networks running on the same channel?
garce
DD-WRT User


Joined: 24 Aug 2016
Posts: 56

PostPosted: Mon Feb 06, 2017 18:12    Post subject: Reply with quote
mgw2011 wrote:
garce wrote:
Windows 10 in several machines.
The strange part is that if I switch to 5GHz it works much better.
One thing, I did created a guest network on 2.4GHz and later deleted it since I thought it was causing some of the "occasional wifi lost" and also at some point several 2.4GHz stopped working

Why not stay with the 5GHz then?

2.4 GHz is usually pretty crowded ... did you check for neighborhood WLAN networks running on the same channel?


Many of the laptops only support 2.4GHz. Also, this is not an RF environment issue. I didnt have this problem on 2.4GHz with my previous router
Xeon2k8
DD-WRT Guru


Joined: 11 Feb 2016
Posts: 1281

PostPosted: Mon Feb 06, 2017 18:24    Post subject: Reply with quote
I would start with erase nvram since you haven't done it under ddwrt for discarding vars issues.
_________________
R6400v2 (boardID:30) - Kong 36480 running since 03/09/18 - (AP - DNSMasq - AdBlocking - QoS)
R7800 - BS 31924 running since 05/26/17 - (AP - OpenVPN Client - DNSMasq - AdBlocking - QoS)
R7000 - BS 30771 running since 12/16/16 - (AP - NAS - FTP - SMB - OpenVPN Server - Transmission - DDNS - DNSMasq - AdBlocking - QoS)
R6250 - BS 29193 running since 03/20/16 - (AP - NAS - FTP - SMB - DNSMasq - AdBlocking)
garce
DD-WRT User


Joined: 24 Aug 2016
Posts: 56

PostPosted: Mon Feb 06, 2017 18:35    Post subject: Reply with quote
Xeon2k8 wrote:
I would start with erase nvram since you haven't done it under ddwrt for discarding vars issues.

Is it advisable to backup my settings, clear nvram and restore my settings?
Xeon2k8
DD-WRT Guru


Joined: 11 Feb 2016
Posts: 1281

PostPosted: Mon Feb 06, 2017 18:39    Post subject: Reply with quote
garce wrote:
Xeon2k8 wrote:
I would start with erase nvram since you haven't done it under ddwrt for discarding vars issues.

Is it advisable to backup my settings, clear nvram and restore my settings?

It would if you come from a clean ddwrt build but since you would be doing a backup from a dirty nvram now, I wouldn't do it. What you could try is, do a backup, clear nvram, and then on that clean state test the 2.4 band, if it works good, try restoring and test again the 2.4 band, if it still works good then solved, if not probably it's something on the old nvram vars.

_________________
R6400v2 (boardID:30) - Kong 36480 running since 03/09/18 - (AP - DNSMasq - AdBlocking - QoS)
R7800 - BS 31924 running since 05/26/17 - (AP - OpenVPN Client - DNSMasq - AdBlocking - QoS)
R7000 - BS 30771 running since 12/16/16 - (AP - NAS - FTP - SMB - OpenVPN Server - Transmission - DDNS - DNSMasq - AdBlocking - QoS)
R6250 - BS 29193 running since 03/20/16 - (AP - NAS - FTP - SMB - DNSMasq - AdBlocking)
blaser
DD-WRT Guru


Joined: 16 Jul 2006
Posts: 504

PostPosted: Tue Feb 07, 2017 0:37    Post subject: Reply with quote
go to settings / wireless, change to wl0 in the menu and run site survey.
Check how many wireless network in the area on the same channel you are running and see if you have any not used.
I had similar issues, eventually I chose
channel 3
NG mixed
wide 40mhz
channel ext upper

solved my issues

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garce
DD-WRT User


Joined: 24 Aug 2016
Posts: 56

PostPosted: Sun Feb 12, 2017 20:33    Post subject: Reply with quote
ok, I am desperate. My isp is 30mbps
1. I did an nvram reset and manually added my settings one by one. Still slow 2.4ghz. Good (maxed) wired and 5GHz was good too
2. I reloaded the brainslayer build mentioned on the wiki. Same problem

I have only set ch=9 (per survey), 40mhz, ng mixed, lower. Everything else is the same
I am sitting 6 feet away from the router with nothing in between.
2.4GHz only gets to 11mbps.
5GHz gets to 29.6mbps.
Is my router broken?
Malachi
DD-WRT Guru


Joined: 17 Jul 2012
Posts: 7221
Location: Columbus, Ohio

PostPosted: Sun Feb 12, 2017 20:54    Post subject: Reply with quote
Only use 20mhz for the 2.4 band too much interference when using 40, too many overlapping channels. Also, it's best to use channel 1,6 or 11.
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I am far from a guru, I'm barely a novice.
garce
DD-WRT User


Joined: 24 Aug 2016
Posts: 56

PostPosted: Sun Feb 12, 2017 22:26    Post subject: Reply with quote
I will retest in the following days. I run out of time today. Also, I started to get good speeds (2.4GHz at 29.6mbps). Strange... before issues were while testing back to back 2.4ghz, 5ghz, lan.
I don't think that channels have anything to do. I am IN FRONT of the router, 6 feet away. I live in a detached home and this is the only router here. I can not remotely believe that in this unrealistic situation, wifi neighbors have anything to do. Maybe if I was trying to download 150mbps and getting 140mbps. But getting less than 1/10th of that in front of the router? (as I mentioned ISP speeds are only 30mbps but I was getting just about that with 5ghz and lan)
I also downloaded an app to test local download speed over wifi but I will test next time.

I will keep monitoring. Thanks
egc
DD-WRT Guru


Joined: 18 Mar 2014
Posts: 6389
Location: Netherlands

PostPosted: Mon Feb 13, 2017 10:52    Post subject: Reply with quote
Could also be interference of bluetooth, USB : http://www.dd-wrt.com/phpBB2/viewtopic.php?t=165678 or cordless phone devices
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Routers:Netgear R7800, R6400v1, R6400v2, Linksys EA8500, EA6900 (XvortexCFE), E2000 (converted WRT320N), WRT54GS v1.
OpenVPN Policy Based Routing: https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=321686
Install guide R6400v2:http://forum.dd-wrt.com/phpBB2/viewtopic.php?t=316399
OpenVPN Server Setup:https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=318795
Install guide R7800: https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=320614
Wireguard Server setup guide:https://forum.dd-wrt.com/phpBB2/viewtopic.php?p=1183135
Wireguard Client setup guide:https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=324624
Wireguard Advanced setup guide:https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=324787
Forum Guide Lines (important read):https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=324087
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