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RT-N66U - Not capable of 300mpbs

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LeeM

Occasional Visitor
Hi,

I have n rt-n66u running firmware "3.0.0.4.374.43_27E5j9527" of Johns.

I have recently upgraded my broadband to 300mbps, however it seems the N66U is struggling to provide this speed and tops out at ~230mbps.

I've monitored cpu whilst trying a speedtest and can see the cpu average shows 1.51 which suggests the cpu is the culpret. However I see on this site that the test shows this router can manage over 700mbps throughput?

I've checked and HW acceleration is enabled and QoS is disabled, so is there anything else that could be limiting the router?

Thanks,
Lee.
 
The CPU usage would suggest that hardware acceleration is not being used. What does it say at Tools > System Information > Network > HW acceleration
 
It might be worth plugging your PC directly into the cable modem (and rebooting everything) and doing another speed test just to confirm that your ISP is actually supplying the bandwidth you expect.
 
OK I just tried direct to the modem and speedtest.net shows 370mbps, i.e. full speed.

So it seems it is the N66u which is struggling :(
 
Is your internet provided by a standard cable modem connection or are you using something like PPPoE or PPTP?

Are you running any non-standard services on the router, like torrents, media server, VPN clients, user scripts?
 
Its a cable modem (virgin media superhub 3 in the UK). I have nothing running on the router at all, not even any external storage plugged in.

Wondering if I should try a hard reset and re-configure everything manually...
 
Wondering if I should try a hard reset and re-configure everything manually...
Definitely worth trying, particularly as it sounds like you don't have too much to reconfigure. I'm assuming you did a hard reset after you first installed John's firmware?
 
I recently moved from merlins firmware to Johns (well actually today as part of this troubleshooting), so no didn't do a hard reset at that point as the thread said it wasn't needed.

I'll try it now and see what happens.
 
Depends what version you were on before.
Installation Notes
  • For supported routers currently running ASUS firmware 380.3000 or above, or Merlin 380.60 or above, you cannot load this fork using the built in firmware update web interface. You must use the ASUS Firmware Restoration Tool from the ASUS support website to install this fork firmware and perform a factory default reset following the firmware update.
 
I was on a version much older than this, hadn't touched it in years :)
I see I need to make an update to the instructions.

...You must use the ASUS Firmware Restoration Tool from the ASUS support website to install this fork firmware. You must always perform a factory default reset following the firmware update when moving from ASUS OEM or Merlin firmware above level 374 .xx regardless if you updated via the web interface or Restoration Tool.
 
Well if its any help I didn't need to do that and the router is running fine, apart from of course the issue I'm discussing here which existed with the original merlin firmware too :)

As soon as the family can live without the internet for an hour I'll do a factory reset anyway and see if that helps.
 
I see I need to make an update to the instructions.
Thanks for the clarification. I think that because there were a few notes specifically saying when you should do a factory reset I'd assumed that anything else didn't require it.
 
VM Hub 3.0 in modem mode (It definitely isn't Super!)? The Arris manufactured Hub 3.0 does have the buggy Intel Puma chipset, but that seems to just give intermittent variable ping spikes not affecting raw throughput on speedtest. I think I get 230 Mbps on the 200 service using HW acceleration no QOS, not too surprised you need a more recent dual core ARM router for more, without HW acceleration speed was more like 150Mbps. I think the upstream increase on the 300Mbps service most useful - it is supposed to be 300/20 rather than 200/12 isn't it? - the asymmetry will make it hard to make best use of the downstream.
 
VM Hub 3.0 in modem mode (It definitely isn't Super!)? The Arris manufactured Hub 3.0 does have the buggy Intel Puma chipset, but that seems to just give intermittent variable ping spikes not affecting raw throughput on speedtest. I think I get 230 Mbps on the 200 service using HW acceleration no QOS, not too surprised you need a more recent dual core ARM router for more, without HW acceleration speed was more like 150Mbps. I think the upstream increase on the 300Mbps service most useful - it is supposed to be 300/20 rather than 200/12 isn't it? - the asymmetry will make it hard to make best use of the downstream.
I get 220/12 on 87U with no HW acceleration, with VM SH3 in Modem mode. And yes, I'm blighted with the Puma latency spikes. Which makes for bufferbloat testing in QoS fun, I might add.
 
Yep I was on the 200 Gamer level which was provisioned as 220ish before upgrading to 300.

Am aware of the puma issues but don't think thats the issue here as plugged directly into the sh3 I get 370mbps according to speed test.
 
OK so I have an update with good news!

I did a factory reset on the firmware i was using which was the latest of johns LTS (374.43_27E5j9527) and then immediately ran a speedtest without changing anything. No joy, same 230mbps limit.

So decided to try the latest merlin fw (380.68_2) and lo and behold I've now got full speed!

Interestingly on the LAN - SWITCH CONTROL page it only shows CTF is enabled:




On the new version there is a nice cpu graph too, so you can see the cpu load whilst doing a speed test. Much better:



Guess I'm going to have to return the new router I ordered last night.... oops !

 
Last edited:

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