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AC68U vs AC3100 vs AC86U wifi testing

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maxbraketorque

Very Senior Member
My RT-AC68U served me well for several years, but I was in need of better throughput at long range, so I finally decided it was time to upgrade. I have been thinking about the RT-AC88U/AC3100 and the new RT-AC86U. The RT-AC88U/AC3100 was more compelling to me based on the available wireless performance data that suggested it would be better than the RT-AC86U, so when the AC3100 went on sale for $170 at Best Buy back in early December, I bought one. Sure enough, it was much better than the AC68U at long range, both for 2.4 GHz and 5 GHz as I noted in a thread I created comparing the two. However, when doczenith1 showed the AC86U to perform much better than the AC68U, I decided to buy an AC8U so that I could compare wifi performance of all three routers and keep the one that I liked best.

The basis for the comparison is file transfers between a wired and a wireless computer on my network. By keeping it within the network, I eliminate potential uncontrolled variations in internet speeds. Since 802.11AC is pretty darn fast when in close range to the router, I needed fast devices for the comparison. I used my 2012 Macmini with an Intel M4 256 GB SSD for the wired device. This computer saturates a 1 Gbps link between it and my ASUSTOR NAS both for read and write of large files, so its a capable computer. The wireless device is a 2016 MacBook Pro. This is one of the few laptops with a 3x3 antenna for both 2.4 GHz and 5 GHz, so speeds will be higher than typically seen for wifi performance testing.

I wanted to understand both large single file and multiple smaller file performance. Multiple read/write assesses not only the wifi but also the overall capability of the router. I tested both read from the wired device and write to the wired devices. File transfers were performed via SMB3 (the standard network file protocol for later versions of Mac OS X).

I ran tests in two locations. The "near field" location is two rooms away from the router two open air pathways for the wifi signal. The "far field" location is at the other end of the house down a hallway. Perhaps more important than location is the signal strength information that is included for the comparison. I think its handy for comparing to Tim's fully isolated tests.

All three routers were tested after installing the lastest OEM firmware followed by a factory reset and then applying my preferred settings. Settings among the routers were as identical as possible. The routers were all placed in the same single location and same orientation. Only one router at a time was tested with the others turned off. I did leave all my wifi IP cameras, my NAS, and phones on the network during testing. None of the devices were transmitting during the tests though.

Testing took several sessions over two days to complete. When starting a new session, I always repeated some of the tests from the prior session to verify that nothing about the test environment had substantially changed. And as needed, I repeated tests to verify trends. Results are in the image below. Here are the key observations:

1) The RT-AC68U does great in near field performance. It essentially equaled or beat both the AC3100 and AC86U in 2.4 GHz and 5 GHz near field performance. For people with a small apartment who don't need VPN performance, the AC68U is a great choice.

2) The AC3100 and AC86U both are clearly much better than the AC68U at far field performance. In some cases, the benefit of these routers over the AC68U is 10x in some cases.

3) For the AC3100 and AC86U, 5 GHz AC far field performance, especially for download, is actually better than 2.4 GHz N despite the lower signal strength for 5 GHz.

4) For the big picture, the AC86U beats the AC3100. In near field tests, the AC3100 appears to have slightly better gross speed for both 2.4 GHz N and 5 GHz AC, but the AC86U clearly does better at multi-file read/write indicating better performance in non-wifi aspects of router performance. In far field tests, the AC86U wins too. Some of the 5 GHz transfer speeds are quite impressive for relatively low signal strength. I really thought that the AC3100 with four external antennas would win, but surprisingly, the AC86U had slightly better signal strength in all conditions.

So it looks like the AC86U is the winner not only for wifi but also for the improved processing power associated with the multi-file transfers. I've mentioned in other threads that the AC86U looks like a replacement for the AC68U and not for the AC3100/AC88U. This seems even more apparent to me when seeing all three routers in real life and realizing that the AC86U is the exact same form factor at the AC68U. I do wonder whether the guts of an AC86U put into AC3100/AC88U format would perform even better than an AC86U. Hard to imagine that ASUS won't have something like that soon.

One final comment I have is that the 5 GHz band on the AC86U became inaccessible during a portion of the testing, and a reboot was required to get it back, so there are clearly some bugs that still need to be worked out as others have said. I'm going to continue using it and will report whether I see more issues.

UPDATE: I seem to have eliminated the 5 GHz band accessibility issue by doing a full reset and manually re-adding the router settings.

wireless performance tests_v2.png
 
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My RT-AC68U served me well for several years, but I was in need of better throughput at long range, so I finally decided it was time to upgrade.
2) The AC3100 and AC86U both are .......
Did you check which channel you used? That plays very important role in my test.
 
Did you check which channel you used? That plays very important role in my test.

All were tested on the same channels - 11 for 2.4 GHz and 36 for 5 GHz. I did later try testing the AC86U on other 5 GHz channels. I created another thread that shows my observations, but to summarize here, signal quality (defined as RSSI minus background) on Ch 36 was slightly better than on the upper channels, and more interestingly, signal quality on Ch 48 was significantly better than on Ch 36.

I did not have the chance to try the same on my AC3100, and its sold now. I could try on my AC68U, but need to make time for it.
 
All were tested on the same channels - 11 for 2.4 GHz and 36 for 5 GHz. I did later try testing the AC86U on other 5 GHz channels. I created another thread that shows my observations, but to summarize here, signal quality (defined as RSSI minus background) on Ch 36 was slightly better than on the upper channels, and more interestingly, signal quality on Ch 48 was significantly better than on Ch 36.

I did not have the chance to try the same on my AC3100, and its sold now. I could try on my AC68U, but need to make time for it.
Thanks for response. BTW, I found channels ~156 has much better range than 36/40 etc. Maybe it depends on house layout.
 
Thanks for response. BTW, I found channels ~156 has much better range than 36/40 etc. Maybe it depends on house layout.

For which router? Or did you see this for several different routers?
 
Thanks for response. BTW, I found channels ~156 has much better range than 36/40 etc. Maybe it depends on house layout.

That's the standard:
Channels 36 – 64 max 200mW
Channels 100 – 140 max 1000
Channels 149 – 161 max 4000
 
That's the standard:
Channels 36 – 64 max 200mW
Channels 100 – 140 max 1000
Channels 149 – 161 max 4000

In 2014, the FCC changed the indoor rules for the UNII-1 channel range (36-48) to match that of UNII-3 (141-165). Client max conducted power is now 250 mW, and Master max conducted power is 1000 mW for both bands. Devices made before 2014 may still obey the pre-2014 FCC rules, but any newer devices should have the same broadcast power on the upper and lower 5 GHz channel ranges. If they don't, then the manufacturer is shooting themselves in the foot.
 
I didn't specify that standard is for Europe.
You are much more lucky because of FCC Part 15.407(a). Although 36-64 are crowded even with a 200mW transmit power.
In Europe we only have 200mW regulation. And Roy2001@ observation is accurate over here ;)
 
I didn't specify that standard is for Europe.
You are much more lucky because of FCC Part 15.407(a). Although 36-64 are crowded even with a 200mW transmit power.
In Europe we only have 200mW regulation. And Roy2001@ observation is accurate over here ;)

ok. I guess I should have asked location, or perhaps everyone should have mentioned their location to add meaning to the discussion.
 
March 9, 2018 Update
Here are some additional comparisons between the AC68U and AC86U. In this case, the routers were placed in the AP location in the downstairs portion of my house. As with my original testing, each router was tested by itself, and the routers were configured as identically as possible to each other. Sorry, I didn't have time to measure speeds, but still some interesting data. RSSI and signal quality are both slightly better for the AC86U, but link rate is much better for the AC86U at lower signal strength. Channel 157 was already determined to be the best U-NII-3 channel for the AC68U. I did a bit of testing, and it seems that channel 153 is probably the best for U-NII-3 on the AC86U.

AC68U vs AC86U link rate and signal.png
 
May be me being stupid but I have an AC68U in the UK and can only select 5ghz channels up to 140. I am using Merlins latest fw. Is there a setting somewhere I am missing?

Looking at a new router for better wireless coverage as the AC68u isn't great in our house, so the AC86u, looks like the best choice.
 
May be me being stupid but I have an AC68U in the UK and can only select 5ghz channels up to 140.
it's absolutely normal.

86u is a good router, have better coverage than 87u, and 68u, but not too much.
 
Well... maybe it's about the time to upgrade my AC68U. But I would probably go with R7800 since we're moving into a bigger home. Throughput at distance is the key.
 
Would you mind posting the hardware revision of the RT-AC68U used for testing? I am wondering if this is representative of current generation RT-AC68U, or more representative of the earlier hardware revisions.
 
Would you mind posting the hardware revision of the RT-AC68U used for testing? I am wondering if this is representative of current generation RT-AC68U, or more representative of the earlier hardware revisions.

B1. Its about two years old, so mid-generation, 1000 MHz CPU.
 
The device they connect to would affect these results also.

The AC3100 wins in most of your mono tests.
 
The device they connect to would affect these results also.

The AC3100 wins in most of your mono tests.

Yeah, for sure client device could affect results. Too many variables to be able to cover all possible aspects of performance.

No doubt the AC3100 is good. I think the AC86U was a little better overall though because of the clearly better 5 GHz performance.
 

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