Review: ASUS RT-AC3100 Extreme Wi-Fi Router


Regular readers will be aware that we’ve recently updated our test methodology for routers. Rather than benchmarking wireless speeds on a single adapter (we’ve been using an AC1200 USB model most recently), where possible, we’ll be running a more comprehensive suite of tests across a range of devices. Network speeds vary greatly depending on both the router and wireless adapter in play. The sub-100 Mbps speeds typically experienced by a smartphone with a 1×1 802.11n adapter pales when compared to the 800 Mbps+ you’ll get with the latest 3×3 or 4×4 802.11ac devices.

The idea is to help you get a clearer view of real world speeds for typical mobiles, tablets, desktops and laptops – we obviously can’t test every device with every router but we can test a number of device classes to bring a little more light and shade into the picture.

Alongside single device throughput tests, we’ll also include a multi-device test that measures network speeds with five devices transferring data to/from an Ethernet connected “server PC” simultaneously. This benchmark provides a really strong, “real world” test that allows us to separate the best from the rest.

All benchmarks are conducted using the industry-standard iPerf 3 application, which works well for us as there are versions available for most operating systems. We calculate average upstream and downstream speeds between the PCs over three five-minute tests (so six runs in total). What you see presented in the charts below are combined averages.

Ethernet Benchmark

First up is the Ethernet test, which sees us connect two Intel Core i5 PCs to the router, one acting as a “server”, the other as a “client”. The ASUS RT-AC3100 came up surprisingly short here, with an average speed of just 829 Mbps. Digging into the results, I found that while the router’s upstream performance was reasonable (if not spectacular, at 903 Mbps), upstream speeds lagged at 756 Mbps. Overall, the RT-AC3100 came bottom of the list of routers we’ve tested in this class for Ethernet performance.




2.4 GHz Benchmark

For our wireless benchmarks, I ran tests at 2.4 GHz and both 5 GHz bands on a variety of wireless devices – smartphones,tablets, notebooks, USB and PCIe desktop adapters – to understand the average speeds available across a range of hardware. This is the first AC3100 we’ve put through our new router testing methodology, so at this point, I cant share like for like comparisons.


As you’d expect, performance varies greatly depending on the wireless adapter being used, but a top speed of 197.2 Mbps is a great result. Indeed, it beats the top 2.4 GHz speeds achieved by both of the AC5400 routers we’ve tested – the ASUS RT-AC5400 (158 Mbps) and the TP-LINK Archer C5400 (177.3 Mbps). While those devices offer an additional 5 GHz band, this dual-band router still delivers.

5 GHz Benchmark

I saw 5 GHz speeds top out at just under 793 Mbps, which is a respectable result, but behind expectations. ASUS’ AC5400 model was able to deliver a huge 929 Mbps and I was expecting something similar with the RT-AC3100 when partnered with a 4×4 adapter. However, you can see that the super-fast ASUS PCE-AC88 was only able to muster 782 Mbps – behind our test iMac, which has an integrated 3×3 adapter. Perhaps ASUS could fine tune performance with 4×4 adapters in a future firmware update. Otherwise, the RT-AC3100 is really speedy.


Multi-device Benchmark (Smart Connect)

Like a few of the routers we’ve tested recently, the ASUS RT-AC3100 features Broadcom’s Smart Connect technology, which automatically groups device connections to specific wireless bands. The idea is to optimise total throughput. Our multi-device test connects five clients (one 1 x 1 device, three 2 x 2 devices and one 3 x 3 device) to the router and measures data transfer speeds in parallel – a great real-world test of the router’s capabilities.

So far, I’ve seen variable success with Smart Connect. The two AC5400 tri-band routers I’ve reviewed recently – the ASUS RT-AC5300 and TP-Link Archer C5400 – have implemented the feature to great effect, boosting average speeds (in aggregate) by around 70%. Other routers have fared less well and the RT-AC3100 unfortunately falls into this category. Enabling Smart Connect actually had a detrimental effect on average speeds, with 471.6 Mbps (disabled) playing 463.8 (enabled).


It’s also here that you’ll find a key difference between this AC3100/3200 device and a more expensive, tri-band AC5300/5400 router. With Smart Connect enabled on the latter devices we’ve tested, we saw aggregate speeds between 750 Mbps up to 930 Mbps on the TP-Link Archer C5400. Dual band devices we’ve reviewed have not been able to get anywhere near those speeds in multi-device tests.

USB Benchmark

When I tested the ASUS RT-AC5300 a couple of weeks ago, I was a little underwhelmed by the router’s USB performance. The same is true of the RT-AC3100. Read/write speeds of 30.8/34.3 MB/s aren’t dreadful, but neither are they particularly special. Sharing a USB hard drive on the network with this router should be fine for basic file transfers as well as well as light media streaming, but don’t expect anywhere near the performance you’ll receive from a dedicated NAS.



If you’re a little confused by the sheer choice of ASUS routers available across the AC3100/AC3200 class, then you can’t be blamed. The company has pushed out a number of similar looking models which include slight variations in features – which one is right for you?

Currently priced around $270, this RT-AC3100 model is the cheapest of the bunch and you’ll get very good wireless performance for your money and the same granular software that’s perfect for seasoned home network admins. Wired performance wasn’t so great, however and if you’re in a home with many devices competing for bandwidth, then you should consider a tri-band AC5300 model.

However, if this is the class for you, then the ASUS RT-AC88U is the better bet for longevity. With eight Gigabit LAN ports on board (compared to just four on the RT-AC3100) you’ll be able to connect many more wired devices to your network. Those additional ports are very handy for anyone connecting smart home devices, many of which require their own wired hub. It’s $20-30 more expensive than this model, but those extra ports are worth the premium.

But if you do opt for the ASUS RT-AC3100, you’ll find yourself with a well-featured router that offers many of the features available in top-class devices. It’s a capable choice for homes with a growing number of connected devices, but can’t quite reach the aggregate speeds available from more capable AC5300/5400 models. That said, if you don’t need all of the advanced configurability provided by ASUS, then you’ll find routers available with similar performance for much less.



  1. Terry,

    I don’t understand this statement:

    I saw 5 GHz speeds top out at just under 793 Mbps, which is a respectable result, but behind expectations. ASUS’ AC5400 model was able to deliver a huge 929 Mbps and I was expecting something similar with the RT-AC3100 when partnered with a 4×4 adapter.

    Why would you expect similar results from the AC3100 as the AC5400? Isn’t that like expecting the same results from Lamborghini Huracan LP 610 and the LP 580? The 610 has 610 metric horsepower and the 580 has 580 metric horsepower. Isn’t the purpose of a more expensive model to get more performance. If the more expensive care performed the same as the cheaper one, who would buy the more expensive model? If you can clear this up, I would really appreciate it.


  2. BEWARE if intending to use this router’s USB ports for storage.

    The “USB 3.0” port is just a blue colored USB 2.0 port, not actually a USB 3.0 port.

    Both USB ports cannot use large drives (around 4TB) since the kernel used by this router has a 4+ year old bug that prevents the OS from being able to address large drives.

    Both USB ports have a maximum read/write speed of around 1.5MB/s…nowhere near the 100MB/s in the specs. While reading/writing USB storage the CPU is maxed out at 100% for both cores so no other functionality can be used (internet access).

    Asus customer support is no help. At first I was told these issues are “normal”…now, 2+ weeks later they have finally started to look into them. Don’t bother with Asus customer support, you won’t get any help unless the case is “escalated” to “Level 2″…this process takes at least a week.

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