Gaming Lag Using Asus RT-AC86U With Merlin Firmware

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Paul Short

Occasional Visitor
Hi Everyone!

In need of some help with regards gaming lag using an Asus RT-AC86U with latest Merlin firmware.

To cut a long story short, our children are off to University, leaving my partner and I the only ones left in the home (peace at last!). We were all heavy internet users so I opted to buy a Asus ROG GT-AC5300 gaming router to cope with the internet demands of the household. I have to say it performed really well, no complaints from anyone about buffering, lag or disconnections. Now it is just us parents left, it seemed a bit overkill to me to keep using the AC5300, so I opted to buy an Asus RT-AC86U for a few reasons. It has a much smaller footprint than the AC5300 and looks more pleasing to the eye in my books, still has some of the gaming features the AC5300 has, and best of all is compatible with Merlin firmware, which I have missed since using the AC5300.

Considering there were no issues using the AC5300 with four of us in the home, I believed the AC86U would be more than adequate a router to handle the needs of just two of us in the home. I am a huge Fallout 76 fan, and regularly play it on my PC, and during the use of the AC5300 I had no issues with gaming lag at all. However, I now have had the AC86U running since yesterday and my gaming experience is totally different with very frequent, short bouts of lag whilst playing FO76. Yes, I do have a lot of devices in the home that require an internet connection, but I have been playing for the last hour, with no one else in the house at the moment, no other devices using any significant bandwidth, using a wired connection between the AC86U and my PC, and the experience is awful, the game will play fine for a few minutes then stutter and freeze for 5 to 10 seconds due to gaming lag. The game played fine yesterday whilst using the AC5300, it's only since changing to the AC86U that these problems have since occurred. I don't believe my internet connection is at fault either as I monitor it with a Raspberry Pi3 running DSLstats and I haven't noticed any odd behaviour, it's always been a reliable, stable internet connection.

I was wondering if any of you guys can give me ideas or advice on why this is happening, and how I might be able to rectify the lag issue on the AC86U. I'd rather not revert back to the AC5300, so any troubleshhoting tips for the AC86U would be really appreciated.

Many thanks in advance.
 

ColinTaylor

Part of the Furniture
Disable QoS and AiProtection and test again when there are no other users on the network. That might help to narrow down the cause.
 

Paul Short

Occasional Visitor
Disable QoS and AiProtection and test again when there are no other users on the network. That might help to narrow down the cause.
Wow, quick response, thank you. I'll try out your suggestions and try again. May take half an hour or so to guage if any improvement but I will let you know the outcome.
 

Paul Short

Occasional Visitor
Didn't take long to realise that disabling those options didn't rectify the issue. Any other suggestions would be appreciated.
 

ColinTaylor

Part of the Furniture
Don't rule out ISP issues (or game server issues). I find that Sod's Law dictates that every time I install some new network equipment that's precisely the same time my ISP decides to do "maintenance". :rolleyes:

What kind of internet speeds to you have? You mention DSLstats, are you on an ADSL connection?

It's possible the problem is caused by something coincidental on your PC, like a Windows update or anti-virus activity.
 
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Paul Short

Occasional Visitor
It's possible the problem is caused by something coincidental on your PC, like a Windows update or anti-virus activity.
That's what I'm beginning to wonder. So I guess it's a case of exercise a bit of patience for now and see if the issue resolves itself in a day or two?
 

Paul Short

Occasional Visitor
Ok, thanks for the suggestions. I'll test the AC86U for a couple of days and see what happens. If all else fails I can revert back to the AC5300 and return the AC86U.
 

ColinTaylor

Part of the Furniture
It might be worth having a look in the router's System Log to see if there any problems reported at the same time as you experience the issue.

As this is a brand new router I'm assuming you haven't installed any third party scripts yet. Have you made any other notable changes to the basic configuration, DNS for example?
 

Paul Short

Occasional Visitor
It might be worth having a look in the router's System Log to see if there any problems reported at the same time as you experience the issue.

As this is a brand new router I'm assuming you haven't installed any third party scripts yet. Have you made any other notable changes to the basic configuration, DNS for example?
I've installed Merlin FW, but that's because I'm with Sky and can use the Option 61 settings to get internet access. I usually change DNS servers to Google's but I have tried reverting back to ISP ones and issue still exists. The only other setting I change is the 'Respond ICMP Echo (ping)' in Firewall for my Thinkbroadband quality monitor graphs.

Nothing to note in system log as far as I can see too.
 

Paul Short

Occasional Visitor
I'm actually tempted to fire up the AC5300 now and see if I get the lag issues. Surely it would be a good test whilst the game is still lagging?

I have noticed the lag seems to happen at almost identical intervals, that seems odd to me??
 

ColinTaylor

Part of the Furniture
I'm actually tempted to fire up the AC5300 now and see if I get the lag issues. Surely it would be a good test whilst the game is still lagging?
Good idea.

I have noticed the lag seems to happen at almost identical intervals, that seems odd to me??
What sort of interval? That might be a clue.
 

Paul Short

Occasional Visitor
Seems like the intervals are about every 2 minutes, no more than that. Just about to test the AC5300 out, I'll let you know the outcome.
 

Paul Short

Occasional Visitor
Good idea.
Ok, I think I can rule out router problems, the lag is happening with the AC5300 now too. I guess as you said it seems like more of a game server, DNS server or PC issue that's the culprit here! I'll probably connect the AC86U back up now and leave it for a while, see if the problem goes away.
 

el pescador

Senior Member
Don't rule out ISP issues (or game server issues). I find that Sod's Law dictates that every time I install some new network equipment that's precisely the same time my ISP decides to do "maintenance". :rolleyes:

What kind of internet speeds to you have? You mention DSLstats, are you on an ADSL connection?

It's possible the problem is caused by something coincidental on your PC, like a Windows update or anti-virus activity.
Or the ISP rolling out the windows update....I presume they do it for MS as it would be cheaper.
If i get a whole day of bad gameplay on Warzone or FIFA can guarantee the Laptop has a windows update ready that night.
 

Trip

Very Senior Member
It appears your behavior samples are randomized enough in time to rule out the fault of Windows Updates, or anything to do with the PC.

I would turn your focus back on the router and VDSL. If I had to venture a guess, I'd say you're probably experiencing a pretty good amount of bufferbloat on the WAN interface of either Asus (neither of which have the proper inner workings to de-bloat as effectively as they could/should, even with Merlin). Id test both Asus routers multiple times at DSLReports.com/speedtest to confirm -- the key metric being your bufferbloat "letter" score. Anything below a "B" and bufferbloat is probably at least a good portion of the root cause. Combine that with possible upstream issues at Sky (prove-able with PingPlotter, run from multiple PCs simultaneously or a single PC at regular intervals), and those two are very likely your culprits.

Presuming the Asus units do score poorly, I'd be interested to see what a single Eero base unit could do for you (~$99), or if you're more skilled, OpenWRT + SQM scripts on a cheaper alternative like a refurb Linksys EA6350v3 ($35 here in the USA). I know you're probably not wild about throwing any more money at the problem, or losing out on Merlin, but honestly if an alternative simply fixes your QoS issues, then I'd say well worth it.
 
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