ASUS PCE-AC66 Wi-Fi AC1750 PCIe Wireless Adapter Review


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Passmark Advanced Network Test Results

The first test was conducted at a distance of 10 feet, which is slightly more than double the minimum recommended distance of 1.5 meters. ASUS suggests reducing the transmitting power of the router and adapter if they are located any closer than 1.5 meters. The default transmitting power is set at the factory to 80mW, and was not changed during any of the benchmarking runs. In this test, the router and adapter were located at approximately the same height and there was a clear line-of-sight between the two sets of 3×3 antennas, with no obstructions. I frequently found that the best signal transfer occurred with all six antennas pointing straight up, vertical. For mobile targets the 45 degree orientation may offer the most stable RF performance, so experimentation is encouraged.

The first thing to note is that these benchmark results show ‘Real-World’ throughput. Nobody using Wi-Fi is actually getting the throughput performance that’s highlighted on the front of the manufacturer’s box. Those are theoretical numbers, and they refer to the raw data bitrate that’s possible with the hardware in question. In this particular test, with the PCIe adapter and router in the same room, I did achieve the theoretical maximum data rate of 1300 Mbps, as indicated by the monitoring software that was included with the Wi-Fi adapter. But, between the data encryption that I was running and the error handling overhead of the various communication protocols, the effective data rate is always going to be much lower. My test results represent what a typical user would experience.


TCP results for the three routers were strong in the line-of-sight test, with the two 802.11n routers pulling in throughputs in the mid 70 Mbps range. The ASUS RT-AC66U easily bested that with 802.11ac performance in the mid 90 Mbps range. UDP performance was another story altogether. The TRENDnet and Linksys routers both threw away more than 80% of the bits transmitted with this protocol. The RT-AC66U had a very low rate of bit loss at this short distance, and there were some trials where there were zero bits lost. That’s extremely rare for a UDP data stream. The effect of all that is clearly shown in the results, where the ASUS pair had an average transmission rate of 369 Mbps and the closest performance with an 802.11n router was 63 Mbps. Clearly, the combination of three data streams and 802.11ac give superior performance. The ASUS PCE-AC66 adapter, matched up with a router that supports the same features, is the only solution that gives you both.


Moving the PC and Wi-Fi adapter into an adjacent room, with double the distance and multiple obstructions between the antenna arrays reduced the effective transmission rate slightly. The ASUS RT-AC66U went from an average throughput of 95 Mbps to 87 Mbps. That’s an 8 percent reduction, but in real life, you probably wouldn’t notice it. The Linksys actually gained two megabits per second in this test, and had an average rate of 75 Mbps. The TRENDnet lost about a third of its throughput, and ended up with a 50 Mbps rate in this test. The UDP benchmarks followed a similar trend, with the ASUS pair still maintaining a throughput well over 300Mbps. The Linksys stayed about the same, and the TRENDnet lost about 30% of its throughput at the longer distance, with obstructions. None of these performance losses would translate to a noticeable difference for web surfing, but file transfers, data backups, or HD video streaming would probably be affected.


Using your Wi-Fi device one room removed from the centrally placed router is hardly the most challenging test, so in order to up the ante I dragged the test PC downstairs to the room that’s furthest away from the router location. That room happens to be the pantry, right next to the kitchen. Both rooms have a high packing density, with lots of wood and metal items to block and deflect radio waves. The only thing more challenging would be to go over to my neighbor’s house, and set up in his kitchen. The higher performance of the 802.11ac standard is really evident here, where the ASUS pairing of PCE-AC66 adapter and RT-AC66U router held on to most of their line-of-sight performance levels. The TCP throughput was back up to 96 Mbps for the ASUS, while the other two routers dropped back to 66 and 51 Mbps. In UDP, the ASUS stayed above the 300 Mbps rate, and the closest the 802.11n routers came was 43 Mbps.


I want to show one chart that demonstrates the beam forming capability of the new 802.11ac products. After about 90 seconds, the Broadcom BCM4360 radio chip that’s inside both the ASUS RT-AC66U router and the PCE-AC66 adapter has completed an analysis of the three separate RF signals going back and forth between the two 3×3 antenna arrays, and has adjusted the phase of each of them to generate a coherent wave front. This has the same effect as making the signal stronger, which then increases data throughput, as you can clearly see. There is an increase in real-world throughput of approximately 20% with this technology, if implemented correctly, as ASUS has done here. This technique is old hat in the RF world – it was invented in 1905 and actually implemented by both sides during WWII. If you ever noticed the four short antennas arranged in a 12″ x 12″ square on the trunk of a police cruiser, then you’ve seen a multiple-input multiple-output (MIMO) antenna system in action. Beam forming was actually introduced in the 802.11n Wi-Fi standard, but hasn’t really been successfully implemented until now, with the new batch of 802.11ac routers coming into the market. The only catch is – you need an 802.11ac adapter that has all the same tricks up its sleeve. The ASUS pair I used in this benchmark use the same Broadcom architecture, and are 100% compatible. There’s been a lot of conjecture about how well this technology was going to work, and now we have the answer.

Clearly, none of these results are anywhere near the typical wired data rates of 1 Gbps. The UDP rates aren’t bad, consistently above 300 Mbps with compatible hardware, but the TCP throughput carries a mighty high burden of communication overhead. Two other things stand out to me, as I review these benchmarks. For a lot of people, the new 802.11ac standard is going to be worth the upgrade costs, in terms of enhanced coverage and increased throughput. Also, there is a very real and measurable difference between the best Wi-Fi systems and the rest. I can’t say that the ASUS PCE-AC66 Wi-Fi adapter is THE best, because I haven’t tested them all. But the features and capabilities you get with this adapter are unparalleled and worth the investment, IMHO. 


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  1. Kzinti1

    According to NewEgg, this thing has been “Discontinued”.
    It may or may not be sold again.
    The main complaint is noncompatibility with the P67 chipset.
    “COMMENT QUESTION: Which “Desktop” PCs are on Wi-Fi in your house?”
    None, here. Just netbooks and one TV so far.
    The real computers are all hardwired.

    1. Olin Coles

      Newegg’s page says “Not available” and “OUT OF STOCK”. It doesn’t say anything like you suggested.

    2. Bruce Normann

      In Stock at Amazon and B&H, and Open Box at Newegg
      Compatibility issue is with Z87 chipset, not P67, AFAIK.
      ASUS is working on the problem.
      I had ZERO issues with my Z68 setup.

      1. Bruce Normann

        PCE-AC66 and newer version, PCE-AC68 are both in stock at Newegg now.

        New version (PCE-AC68) is: newegg.com/Product/Product.aspx?Item=N82E16833320173

        Don’t know yet if there is an upgrade path.

  2. mononymous

    P67 is just one of many Intel chipsets anyway, so it shouldn’t be a major factor in deterring people… anyway mine with the X79 works just fine.

    Previously I used a powerline based network as I didn’t have the luxury of drilling holes into walls. The powerline works ok…ish but after upgrading to fiber it didn’t make sense to stick around with a 200mbps network when I can get something better.

    Currently, I pair this with the RT-AC66U, a Wifi ac capable router from Asus. I have a wall separating myself and the source and the distance is about 10m. Maximum would be at ~850mbps so I still get close to a standard gigabit connection so I’m content with the current setup.

    1. Bruce Normann

      I’m curious what kind of encryption you are using.

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