# Asus RT-AC66u/w, network freezes during Large downloads? help please



## jboydgolfer (Oct 19, 2016)

Hello TPU,

So I have a Asus RT-AC-66w(same as "u" model, except white). I have My windows 10 PC connected through CAT6 ethernet cable, and a "normal" amount of other devices that are connected wirelessly.

The problem is as follows.
ONLY when i download large files, games, etc.. basically, when My ISP's bandwidth provision is being totally utilized, (70mb/s +/- 10mb/s) NOTHING else can be done on the network, not on guest, ethernet, or any other services , you cant even log in to the router during the usage of this bandwidth, its crazy.
During Steam game downloads is when I see this issue, and for the LIFE of me i cannot figure out what the hell to do, other than throttle the steam connection, but that seems silly. I know the AC66u isnt the highest end router in the world, but it should CERTAINLY be able to handle around 8MB/s download..or am i wrong?
I have just now run into this issue again, i am the ONLY device on the network right now. I will bullet point the important shit at the bottom for the TLDR's...

main info, bullet points.....for tldr's
Asus AC66u *latest Merlin FW. 380.62_1*

is this normal when maxing out ones ISP bandwidth allotment??

when all of my bandwidth is being used(75 or so mb/s), the router shits the bed (but keeps the download that caused it connected and running) but all other network devices are unable to load web pages, or anything else online.

PC in specs

currently trying to DL Fallout 4 aka. 24Gb's of data @ max ISP provision.

router allows no page loading on ANY device  during this utilization , not on guest, or other networks, not over ethernet on another PC, nothing, cannot even log into wireless networks.

I noticed that the CPU utilization is 100% during the dowloading of Steam games..maybe that is the Cause??







Any useful ideas or solutions to this issue would be Greatly appreciated.

what i have done....
I have port forwarded Steam's ports...
I have latest FW
I have latest Steam client
I KNOW I can throttle the steam connection
I know I can DL when noone else is around,
but im looking for a solution, not a Resolution to this issue.

Thanks in advance for any useful help.


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## RandomSadness (Oct 19, 2016)

Do you have DoS protection enabled in your firewall settings? If so, turn it off and check if the CPU utilization is lowered.


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## jboydgolfer (Oct 19, 2016)

i am almost 100% certain i Do, ill check it off, and check back in , thanks for the idea, i didnt remember that. currently on the phon with Asus Service too...

edit**  nope still 100% without DOS protection on


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## Athlon2K15 (Oct 19, 2016)

router is too old and slow. that router might as well be a wireless N solution. its a Broadcom 4706 @ 600MHz


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## jboydgolfer (Oct 19, 2016)

AthlonX2 said:


> router is too old and slow. that router might as well be a wireless N solution. its a Broadcom 4706 @ 600MHz



thanks for that help

*general comment*
Asus classes this as a 1750AC, which is pissing me off, since im only using 75mb/s or 8MB/s, i dont know what they use to measure bandwidth, but either way im nowhere near the max, or even a 1/4 of it.


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## RandomSadness (Oct 19, 2016)

That most likely appears to be a firmware issue, can you possibly install an older or third party one(Tomato, DD-WRT)?
What's your packet loss rate?
Do a file transfer using Ethernet on both ends to see if it's really a throughput-related issue. I'm on a DSL-N66U and can max out the GbE LAN without issues.

Edit: Just to rule that out, can you try a CAT 5/5e cable on another port?


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## Kursah (Oct 19, 2016)

I had this issue, but iirc you can enable DoS protection and that should help, though any extra features you enable will utilize more CPU. 

I'm trying to remember what else I may of done to mitigate the issue but its been so long. Doing some research I found that possible solutions.

Do you have a USB storage device connected? If so can you either remove it or run a Health Scan on it from the WebGUI?
Can you disable IP Traffic Monitoring and test again?: Tools > Other Settings > Enable IP Traffic
Are you running any VPN tunnels or servers on the router? If so can you disable them?
Are then any extra features you can disable like QoS? 
Would you be willing to try DD-WRT or Tomato? Could be Merlin and AsusWRT issue...I have read that this year they've had some issues with the WebGUI causing high CPU loads...

What is the rated speed of your Internet? I do see many folks saying 150-200Mbits is really the max WAN traffic these can handle...yet in other threads I've read of users 

If push comes to shove...I do have an Ubiquity EdgeRouer Lite3 that I'm no longer using (saving as a failover) I would be willing to part with. Excellent router, then you could setup your AC66W in Access Point mode. Excellent combo for that BTW. The ERL has a bulkier WebUI and you can do advanced configs via command line interface...that scares most users but it's not hard to do with UBNT routers...just takes time. Not saying you should give up now tho...


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## jboydgolfer (Oct 19, 2016)

RandomSadness said:


> That most likely appears to be a firmware issue, can you possibly install an older or third party one(Tomato, DD-WRT)?
> What's your packet loss rate?
> Do a file transfer using Ethernet on both ends to see if it's really a throughput-related issue. I'm on a DSL-N66U and can max out the GbE LAN without issues.
> 
> Edit: Just to rule that out, can you try a CAT 5/5e cable on another port?



i THINK i might have fixed it, but i cant figure out which setting was causing the issue. By "fix" i factory reset it Again, and for whatever reason this time it stopped the issue, i tried it b4 and it didnt work, i suppose ill go thru and try to single out the damn cause tho.



Kursah said:


> I had this issue, but iirc you can enable DoS protection and that should help, though any extra features you enable will utilize more CPU.
> 
> I'm trying to remember what else I may of done to mitigate the issue but its been so long. Doing some research I found that possible solutions.
> 
> ...



no usb in it.
tried both Merlin current, and Asus factory, seems fixed now, but i still dont know what the cause is/was. ill update when i have the time to hunt it down, right now im making chicken pot pie 

thank you for helping out 

here it is while downloading @ 9MB's/s and several other things now...


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## Kursah (Oct 19, 2016)

jboydgolfer said:


> thanks for that help
> 
> *general comment*
> Asus classes this as a 1750AC, which is pissing me off, since im only using 75mb/s or 8MB/s, i dont know what they use to measure bandwidth, but either way im nowhere near the max, or even a 1/4 of it.



Be careful mixing WAN and LAN ratings. 1750 is the combined maximum theoretical wireless throughput of the router and that's all. It was pre-AC official spec too.

WAN or Internet side is handled differently than LAN, especially because of NAT and firewall filtering. Your LAN throughput should be able to hit 100MB/s over Ethernet which is close to Gigabit speed...and maybe around 2/3 of that at best over WiFi...probably closer to half.

Many home grade routers aren't rated for faster WAN connections...but 75 down isn't abnormal so.it really shouldn't have issues. I've read of guys using this same router over 200 Mbit WAN. I've never had over 60 at home so...

Anyways...felt that needed cleared up.


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## jboydgolfer (Oct 19, 2016)

Kursah said:


> Be careful mixing WAN and LAN ratings. 1750 is the combined maximum theoretical wireless throughput of the router and that's all. It was pre-AC official spec too.
> 
> WAN or Internet side is handled differently than LAN, especially because of NAT and firewall filtering. Your LAN throughput should be able to hit 100MB/s over Ethernet which is close to Gigabit speed...and maybe around 2/3 of that at best over WiFi...probably closer to half.
> 
> ...



 Yeah I am not clear on how they read their band with rating but I am aware that others have used it with much higher ISP throughputs and not had any issue technically my ISP provision is 60 Mb per second but I normally get around 70  to 75 Mb per second over cat six


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## Kursah (Oct 19, 2016)

Band ratings are different and are affected by how many active MIMO antennas there are... the more MIMO antennas, (Multi-In/Multi-Out), so they can add bandwidth on top of bandwidth. Standard AC is 433Mbit iirc... MIMO is 866, adding more adds on top of those. As I said before, this router was one of the first good AC routers, but was released before the official AC draft was passed. Regardless...its ratings are really no different. For you to reach their maximum theoretical bandwidth (which won't happen completely...hence theoretical)...you'll need a AC MIMO router and AC MIMO wireless adapter/device, and correct wide-band configuration if you're not in an overly saturated area wifi-wise. Frankly it's not worth fussing too much about...just know you'll never match Ethernet speed wirelessly on that router or most any router...without spending A LOT of money for router and client devices, and even then latency and bandwidth will still likely be worse.

As always if you want the best speed and latency, it'll be found over an Ethernet or Fiber cable.


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## newtekie1 (Oct 19, 2016)

jboydgolfer said:


> Yeah I am not clear on how they read their band with rating but I am aware that others have used it with much higher ISP throughputs and not had any issue technically my ISP provision is 60 Mb per second but I normally get around 70  to 75 Mb per second over cat six



Yep, I use a RT-AC66U with my 150Mb/s comcast connection and don't have any problems with it.

In reality, modern router CPUs are way over-powered for most internet connection and home network users.


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## jboydgolfer (Oct 19, 2016)

Kursah said:


> Band ratings are different and are affected by how many active MIMO antennas there are... the more MIMO antennas, (Multi-In/Multi-Out), so they can add bandwidth on top of bandwidth. Standard AC is 433Mbit iirc... MIMO is 866, adding more adds on top of those. As I said before, this router was one of the first good AC routers, but was released before the official AC draft was passed. Regardless...its ratings are really no different. For you to reach their maximum theoretical bandwidth (which won't happen completely...hence theoretical)...you'll need a AC MIMO router and AC MIMO wireless adapter/device, and correct wide-band configuration if you're not in an overly saturated area wifi-wise. Frankly it's not worth fussing too much about...just know you'll never match Ethernet speed wirelessly on that router or most any router...without spending A LOT of money for router and client devices, and even then latency and bandwidth will still likely be worse.
> 
> As always if you want the best speed and latency, it'll be found over an Ethernet or Fiber cable.



yeah, ive been cat6 for a while now, and b4 that cat5, always Ethernet though, my kids, and other family use ethernet though, except my daughter, she is ethernet too.
a friend does work for MIT here in Massachusetts, and He gets "free" goodies, like Ethernet, and some other goodies, so i always go Wired when possible.

**edit**
i still havent pinned down the cause of that original issue, but after going full stock, and one by one resetting my preferences, its kicking ass.


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## Kursah (Oct 19, 2016)

Good to hear! Funny part of the reason I recall going to Merlin was that issue..lol maybe the flash procedure cleared out the bug!

CAT6 is good stuff...especially when 10 gig infrastructure goes more mainstream in a few years (or more...). By the time it does SSDs will be far more mainstream so that extra bandwidth will be sooooo nice for network shares!


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