Edimax EW-7822UAC serious performance problems

[Alex Atkin UK]

I recently bought a TP-Link Archer C7 to try and improve the WiFi problems I have been having on my Galaxy Note 3. (suddenly stops transferring data without warning)

I figured while I was doing that I might as well have a dongle around for if I need to do any data transfer on my tablet/laptop so I ordered the Edimax EW-7822UAC as it seemed to be decent for the price. The problem is, I'm not getting the performance I expected and its proving to be totally unstable on my Asus T100-TA which is what I primarily bought it for use on.

Actual performance is measured using iperf.

Galaxy Note 3:
Link speed 433Mbit, actual performance 239Mbit down, 266Mbit up. This is consistent test after test, always above 200Mbit.
This is exactly in line with where I would expect performance to be on a single stream 802.11ac device.

Edimax EW-7822UAC:
Windows 7 i5 2500K (plugged into Renesas USB 3.0 port about 3m away from router through a wall):
Link speed 650Mbit, actual performance 125Mbit down, 152Mbit up.
Windows 7 i5 2500K (plugged into Renesas USB 3.0 port with extension cable so its only 2m away from router clear line of sight):
Link speed 867Mbit, actual performance 177Mbit down, 157Mbit up. I ran this test many times moving the dongle/antenna and router around to try and get the very best possible performance.
Windows 7 i5 2500K (plugged into Intel USB 2.0 port):
Link speed 867Mbit, actual performance 141Mbit down, 92.8Mbit up.
Fedora 20 i5 2500K (plugged into Renesas USB 3.0 port with extension):
Link speed 867Mbit, actual performance 199Mbit down, 243Mbit up.
Fedora 20 i5 2500K (plugged into Intel USB 2.0 port):
Link speed 867Mbit, actual performance 205Mbit down, 238Mbit up.

Most importantly though, it runs like crap on my intended device:
Windows 8.1 Asus T100TA with Windows 8.1 drivers auto-installed:
Constantly failed to connect to any 5Ghz network and the few times it did connect failed to pass any data.
Windows 8.1 Asus T100TA with Windows 8.0 drivers from website:
Link speed 867Mbit with iperf reporting 116Mbit down, 106Mbit up.
Windows 8.1 Asus T100TA with TP-Link TL-WDN3200 (802.11n dual-stream 300Mbit):
Link speed 300Mbit, actual performance 119Mbit down, 96.8Mbit up.
Windows 8.1 Asus T100TA (802.11n single-stream 150Mbit):
Link speed 150Mbit, actual performance 79.3Mbit down, 52.1Mbit up.

How on earth can it be performing worse than my Galaxy Note 3?
Anyone else had problems like this and/or can recommend a USB dongle that actually works properly with the C7?

The Asus USB-AC56 also has favourable reviews but I see suggestions that it may even be the same dongle with a different form factor. In that case I would end up with the same problem.

I suppose I could be lucky and find this is all caused by the antennas being terrible on the Edimax branded dongle, I have seen two identical chipset dongles perform wildly different before. But should I just wait and see if three-stream dongles will ever turn up? Its not worth keeping hold of this one unless it managed at LEAST double 802.11n speeds, consistently.

 

[remixedcat]

Nobody in all the testing I've done (consumer or enterprise) has delivered even close to 867Mbits/sec. I'm seeing more in the range of 170 some to 200 some and occasionally some 300 some mbps....

 

[azazel1024]

It sounds like it could be crap drivers, especially for windows. However, there could be other reasons. Anything else running at the time of the various tests? On your T100 (I also have one), are you plugging it in to the USB3 port or the micro USB port with an OTG cable?

I would not use iperf for the testing, I'd use actual file transfer speeds. I know a lot of people swear by iperf, but in my experience iperf OFTEN under reports actual file transfer speeds. Try actual file transfers using the USB dongle and see how it goes.

 

[Alex Atkin UK]

I don't expect 867Mbit, but I thought it would at least approach half that especially after my Note 3 was able to achieve 266Mbit from a single stream.

From most of the tests I have seen though it does seem performance is not as good as you would expect from adding extra streams, at least not on USB adapters. The only people who really got decent results are using the Intel PCIe card it seems, lets hope second generation USB adapters come out soon and perform decent with first generation APs.

Nobody else using 5Ghz around here except my old network (which I tried on and off) and my Wii U (which was in standby so not transmitting anything noteworthy).

I have returned the adapter now but am still interested in any reports of people having decent performance with this adapter, or the Archer C7.

I never did actual file transfers as the adapter was so unstable on the T100 and with little space on the eMMC (which is not exactly fast either), I felt it would bottleneck. It was kinda at that point I realised that perhaps there is no point in 802.11ac on the T100 anyway.

 

[azazel1024]

I don't expect 867Mbit, but I thought it would at least approach half that especially after my Note 3 was able to achieve 266Mbit from a single stream.

From most of the tests I have seen though it does seem performance is not as good as you would expect from adding extra streams, at least not on USB adapters. The only people who really got decent results are using the Intel PCIe card it seems, lets hope second generation USB adapters come out soon and perform decent with first generation APs.

Nobody else using 5Ghz around here except my old network (which I tried on and off) and my Wii U (which was in standby so not transmitting anything noteworthy).

I have returned the adapter now but am still interested in any reports of people having decent performance with this adapter, or the Archer C7.

I never did actual file transfers as the adapter was so unstable on the T100 and with little space on the eMMC (which is not exactly fast either), I felt it would bottleneck. It was kinda at that point I realised that perhaps there is no point in 802.11ac on the T100 anyway.

Oh wait, I just read this. So that performance for the note3 was with the internal note 3 adapter? If so, then I'd just say a crappy USB dongle.

Yeah, I would rather like better performance with my T100 on wireless. Average is right around 75Mbps with it varying from 70-85Mbps. Not horrible, but still thumb twiddling performance when you are trying to grab a 3GB movie off the network.

My general solution for big files is I just connect my USB3 gigabit network adapter and wire it in. I get around 110MB/sec reads and 32MB/sec writes off the eMMC with it over my network. ~20/20MB/sec read/writes from the micro SD card slot. Even if a lot of times I am grabing a video to micro SD, 20MB/sec is a lot better performance than 10MB/sec.

Check out SNB USB AC adapter review. There were several other adapters they tested and you might have better performance with one of them.

 

[Alex Atkin UK]

Yeah I looked at the reviews on this site first. The thing is the Edimax came second with the one in first being the same chipset, so if its a chipset problem it won't be any better.

Like you said, even a small improvement can be a pretty huge difference on large files. I'm totally out of ethernet ports and short of space to get a bigger switch, so an 802.11ac dongle capable of close to what my USB 2.0 Gigabit adapter could do seemed a good compromise.

I have seen one or two reports of people getting ~500Mbit on 3x3 devices and me getting 266Mbit on a 1x1, it seemed plausible to get somewhere between 300-400Mbit.

 

[stevech]

... even a small improvement can be a pretty huge difference on large files. I'm totally out of ethernet ports and short of space to get a bigger switch.

Really? You are doing large-file transfers on WiFi because you have no switch ports? Geeze. Switches are low cost and are the smooth road. Just daisy-chain a $30 gigE switch.

 

[Alex Atkin UK]

Really? You are doing large-file transfers on WiFi because you have no switch ports? Geeze. Switches are low cost and are the smooth road. Just daisy-chain a $30 gigE switch.

What part of "do not have the space" did you not understand? Also, how is it unreasonable to want to use 802.11ac for what its designed for? Its not like I am doing large file transfers on a daily basis on a tablet with only 32GB storage. The point was to have the OPTION, or for when I work on friends PCs, so I don't have to muck up my wiring and dangle ethernet cables across the room.

As for switches, I have a 5 port router in my server closet, a 5 port hooked up to my Atom router PC, an 8 port switch in the living room and a 5 port upstairs. According to the switch manuals you aren't even supposed to have that many unmanaged switches on a LAN but I cannot combine those first two into a single 16 port because they are both WiFi APs. One of them will be swapped for the Archer C7 as soon as I can get OpenWRT on it with working 802.11ac, so I can unlock the WAN port as a proper switch port.

Adding another switch, not exactly helpful. Temporarily unplugging stuff, I have broken a LOT of cables (especially HDMI) doing that because the large switch is in my media cabinet under the surround receiver so a TON of cables that get tangled up and can't really be handled with cable management either.

 

[azazel1024]

You can more or less have as many unmanaged switches as you want within reason. The only issue you might eventually run in to is running out of MAC address tables on them, as they tend to have smaller MAC tables than semi-managed and managed switches do.

However, you are talking probably in to at least the mid to high hundreds of networking devices before that might be any kind of possibility.

It sounds like you do need better network layout and/or location for a core switch with more ports, or dangle another 5/8 port somewhere.

That aside, I can understand wanting better performance out of your wireless. You could try a different 11ac wifi dongle and see if that shows any improvement. To go back to the Eidimax, did you check the link rates in network properties? Especially on the T100, are you sure whether or not it is actually linking at 867Mbps? It sounds like it is linking at 300Mbps on 2.4GHz instead.

Anyway, dunno. With my setup I have a couple of 16 port semi-managed switches down in my basement storage room with my server and some other networking equipment. LAN drops through most of my rooms (usually just a single one, sometimes several like in my basement office) and my router and AP server double duty as WLAN devices and switches. On my T100 I do most things wirelessly, but if I have a sufficiently large file, I just break out my USB3 GbE adapter and plug in to a LAN drop or in to the AP sitting on top of my entertainment unit. I have been playing with the idead of an 11ac USB dongle for it instead, since I am mostly storage bound with a lot of stuff and that is slightly faster/easier to do. If you offload some of the switching duties to an actual switch from your router/AP, I assume they are sitting semi in-the-open, then plugging/unplugging from them might not be a hassle.

Another question on both the desktop and T100, are you disabling any internal/other Wifi adapter in the machine BEFORE you are testing the USB dongle?

 

[Alex Atkin UK]

I mentioned all the link rates on my first post. Yes I disable the internal WiFi before testing.

Its highly suspect though that the drivers Edimax recommend (Windows Update) refused to work at all. Also the Linux test was done with the official open source chipset drivers patched for my kernel, which is why I am concerned a card with the same chipset would have the same issue.

Like you said, most transfers on the T100 are IO bound anyway so 802.11ac "should" work out not much slower than GbE if it had worked as planned, which is why it seemed more sensible than messing with cables. Its particularly awkward on the T100 if you use it plugged into the charger as the microUSB port feels so fragile that trying not to trip over an ethernet cable AND the charge cable, coming from different sides of the machine, is a concern. If the AC dongle had worked I would probably have bought a short USB3.0 extension and used velcro to stick it to the back of the tablet.

 

[azazel1024]

Dunno. I almost never use my T100 while plugged in to charge. Battery life is good enough I think the only couple of times I have is with VERY heavy games, like KSP and Star Craft 2, just because the battery life is only about 4-5hrs at best running them, especially star craft 2 multi as CPU, GPU and Wifi are all getting hammered.

Otherwise 99.9% of my use is while unplugged.

As for the adapter, you could look at SNBs list of USB 11ac adapters. It looks like there are two chipsets in vogue with the dongle adapters, at least dual stream adapters, right now. You could try out one of the ones with the non-Realtek chipset in it and see how it goes. Or look for a single stream adapter. 433Mbps if the dongle is good should still pan out to 150-200Mbps range in actual transfer speeds. THAT would be a noticable step up from the T100 internal adapter (I can get in the 80Mbps range on mine).

Its kind of one of those things I am looking for is inexpensive and good single stream 11ac USB adapters (oh and small). Might be awhile before that happens. I don't need big range nor huge speed, just something noticably better than the 150Mbps max link rate I can get on my T100 now would be nice sometimes and something small means I could probably just leave it in the dock most of the time or leave it in my tablet bag.

 

[Alex Atkin UK]

I never get as fast as you from the built-in adapter, although perhaps that is an iperf issue?

If you look at my first post again you will see I already have a dual-stream 802.11n adapter which gets 119Mbit down, 96.8Mbit up. That is about double what I get (on average, my first post is all peak-speeds) from the built-in adapter.

To be honest I don't think I ever do enough data transfer to warrant bothering about this, it was just a nice idea at the time for the price but if I have to pay double for a better adapter its not worth it.

 

[remixedcat]

try the base Realtek driver for the adapter (it's a realtek based adapter) and see if you do any better: http://www.realtek.com.tw/DOWNLOADS/downloadsView.aspx?Langid=1&PNid=13&PFid=21&Level=4&Conn=3

Note: completely remove the Edimax one before proceeding

 

[Alex Atkin UK]

try the base Realtek driver for the adapter (it's a realtek based adapter) and see if you do any better: http://www.realtek.com.tw/DOWNLOADS/downloadsView.aspx?Langid=1&PNid=13&PFid=21&Level=4&Conn=3

Note: completely remove the Edimax one before proceeding

A couple of problems with that.

a) I have returned the adapter because it was consistently bad on different OS with different drivers, including Linux which by its nature uses the stock Realtek source code.
b) There are no drivers for the AC chipsets on their site anyway.