Extremely slow download speeds while using AES encryption

I have a Dell XPS 15 (L502x) laptop with an Intel Centrino Advanced-N 6230 wireless adapter. The router in use is a brand new Linksys E1500 with a Motorola SB6120 DOCSIS 3.0 cable modem. Don't know if any of that matters because I am an intermediate user at best when it comes to this kind of thing.

Anyway, I just set up the brand new router and immediately noticed abysmal download speeds of less than 0.5 mbps, although ping was fine. Did some tweaking and found that download speeds increased to ~18mbps, which is I think what I'm paying for, if I only use WEP encryption or if I change the encryption from AES to TKIP while using WPA2 Personal. So I guess somewhere along the line, this configuration does not like AES encryption.

Yes, I have the latest firmware for the router and the latest driver (14.2.0.10) for the 6230, directly from Intel's site and not Dell's.

Any clues as to why AES is so dreadfully slow and how to fix it? If not, I will just keep using TKIP. Not like I know what the difference is, anyway. :]

 

Usually WPA2/AES is the preferred for better N speeds. But, whatever works.. If it makes no difference to you, go with what's fastest.

Also remember that if you use non N devices on the same router it'll cut back on your speed (unless running dual band I believe, but you aren't).. Doesn't address you problem, but something to think about if it's a "family" router

 

That is weird indeed. One thing that stands out is Intel 6230- this card seems to be causing lots of problems.
If you have any other wireless N devices switch of the notebook in question, reboot the router and test if WPA2+AES works fine with a different device.

BTW what is the connection speed (not the throughput- just the speed Windows says it's connected to the router) when WPA+AES is on and what's the connection speed with WPA2+TKIP?

 

The 4 devices using the router are the laptop, a PS3 slim, Wii, and 3DS. So, I believe the PC is the only N device, but usually it's the only one using the router at all.

Also, maybe another interesting thing to note is that upload speed is always around 3.75 according to speedtest, and ping is always 0-5 ms, no matter the security or encryption method. I dunno. Anyway, here are some more in depth results:

WPA + AES = 54.0 - 130.0 Mbps (Windows; yes, it was actually fluctuating, dunno if it's supposed to do that), 0.27 Mbps (Speedtest), 4-5 bars signal strength

WPA + TKIP = Always 54.0 Mbps (Windows), 17.87 Mbps (Speedtest), always 100% signal strength

WPA2 + AES = 54.0 - 130.0, 0.33, 4-5 bars

WPA2 + TKIP = Always 54.0, 17.86, always 100%

 

My suspicion was correct- AES is not the problem- wireless n is.
To run in 802.11n mode you are required to use WPA2+AES, if you change to WPA2+TKIP you can't be using 802.11n anymore and the router falls back to 801.11g (hence 54mbps connection speed)

Notice that you are always running fine when your speed is synced at 54mbps.

Two things to check- advanced tab of Intel driver- check if there's something interesting in regards to 802.11 b/g/n modes.
Second thing- login to your router and choose 802.11g and WPA2+AES- if my theory is correct that should work flawlessly as well.

If you don't do wireless LAN transfers you may stay with 802.11g and WPA2+AES unless your connection speed to your ISP is 20mbps or higher.

Download speed of ~17mbps your getting may be the limit of 802.11g not your connection. Can you do a speedtest while connected via Ethernet?

EDIT: Another possibility- check if "n" works fine with 20MHz channels

 

Yeah, it's in a probability a settings problem. I have a wii, PS3, iTouch, X360 connected to a Linksys E3000 on top of 5 computers and if i connect the computers on the 2.4GHz network, i get a stable 150mbps connection according to Windows. The network is set to mixed mode though and falls back on 20Hz since there are a lot of networks in range.

 

Hey, I really appreciate the posts, guys. Thanks to your tips, I found something that definitely changed something.

downloads, you're absolutely right in that it's 802.11n, not just AES. I disabled n in the advanced tab of the driver properties, and speeds went up to normal.

I then tinkered with several of the other settings in the advanced tab but noticed two things in particular:

1. The value for "Ad Hoc QoS Mode" was "WMM Disabled," whereas in the router's configuration screen, when I went to the Applications & Gaming tab followed by QoS, I noticed that "WMM Support" was ENabled by default. First, I tried enabling it in the driver's options which did nothing. Then I tried disabling it in both options, and I am now at ~22 mbps on speedtest, the same I get while directly wired to the modem. Honestly, I have no idea what this WMM thing is or does, but I guess it should be off, or else 802.11n doesn't work?

2. I also noticed in the driver's advanced settings that the value for "Wireless Mode" is set to "802.11a/b/g" but there IS no option for 802.11n there. a/b/g is as far as it goes. Is that normal? There is, however, a separate property called "802.11n Mode" which is of course enabled. That's the option I tried disabling to make sure that n was truly the problem.

Well, hopefully with the disabling of WMM support, the problem is solved, but please let me know if that is something that should be enabled and if perhaps the problem still lies elsewhere.

Thanks again for so many tips.

Edit: Also, the connection speed according to Windows is now a steady 54.0 mbps with WMM disabled, and this is with WPA2 + AES now.

 

It's because WMM is required to achieve 802.11n speeds so with WMM disabled you'll fall back to 54mbps connection.
So far it's functional which doesn't mean we've solved the issue- we're still unable to get to "n" speeds.
I'm out of ideas at the moment- anyone else willing to chime in?

 

Oh, nuts. Well, at least my speedtest results are a little better than they used to be, and 802.11n is technically enabled.

So the fact that 802.11n is not listed as an option for "Wireless Mode" is not a concern?

Also, I don't know how much faster it would get since ~22mbps is what I was seeing directly wired to the modem... In any case, it would still be cool to get to the very bottom of this, if possible.

 

you could try uninstalling the intel v14.2 in safe mode, reboot with networking then install v14.1 (also in safe mode). reboot and see if that helps anything.

http://downloadcenter.intel.com/Det...it*&DownloadType= Software Applications #help

 

Well it wouldn't be any faster since limit for 802.11g is somewhere between 20 and 25mbps but current situation is just a work-around not a solution.
It's fine as long as you don't upgrade your connection or want to transfer files on LAN at which point Wi-Fi (at its current speed) will limit you.

 

If you don't mind loosing the functionalities other than wi-fi, you could also install the drivers for the 6200. The 6230 and 6200 both have the same wi-fi radio so they should work with the 6230. I remember one guy fixed his wireless issues that way, i can't remember if he had a 6230 or a 6205 though.

 

Just got done trying the other drivers to no avail.
Just for laughs, here are the options listed under the advanced tab of the driver properties and what they are set to by default:

802.11n channel width for band 2.4: 20 MHz only
802.11n channel width for band 5.2: Auto
802.11n Mode: Enabled
Ad Hoc Channel 802.11b/g: 1
Ad Hoc QoS Mode: WMM Disabled
Bluetooth(R) AMP: Enabled
Fat Channel Intolerant: Disabled
Mixed Mode Protection: CTS-to-self Enabled
Preferred Band: 1. No Preference
Roaming Aggressiveness: 3. Medium
Transmit Power: 5. Highest
Wireless Mode: 6. 802.11a/b/g

There are also a couple of wireless adapters installed with the driver every time called Virtual Wi-Fi Adapter... Those aren't relevant to the issue, are they?

 

They shouldn't be, your config seems identical to the one i have on my 6200 and they work perfectly.

 

you have another N card to try?

I feel like I remember there being a weird batch of 6230 cards shipping with the xps line. Could see if another card works. They can be had for under $20 on amazon.. Or get dell to send you another one..

 

Funny you should post that now - I just came back to give a quick update:

I contacted Dell's live chat and linked up with a rep who basically tried everything that I already tried, messing with various settings in the advanced tab of the driver, confirming everything was up to date, rebooting in safe mode, etc. The problem was not resolved but he put in a dispatch for a technician to come and replace the card. At this point, with all the stories of bad experiences with this particular card, it seems to be the most likely explanation. But hopefully the one replacing it won't be equally defective.

We'll see in a few days.

By the way, the very first thing he tried was to disable the bluetooth amp which did nothing. My BT drivers are up to date as well, but is there commonly a problem with the combination of BT + the Intel 6230 card?

 

As far as I know there are issues with this combo although it's not 6230 + BT since 6230 is a 6200 + BT.

 

Actually...I think I knew that from Dell's website. >_>

 

The 6230 was replaced today. Quickest tech visit I've ever had, but the problem lingers. Seems like I have no choice but to live with what I've got and keep WMM disabled. I'll probably contact Dell about it again at some point, but I'm a little burned out on the issue right now, and it frankly works well enough (I just wish I could know it was working PROPERLY). They did want to know if the replacement solved the issue. But, what else would they do? Swap it again, this time with a 1030? I feel like that's the only other possible thing to try.

 

You could just buy a new card if you really need the LAN speed. At this point you're just working @802.11g speeds due to WMM being disabled.
It's not like there's anything wrong with it. If you don't transfer large files on LAN you won't even notice the difference.

 

Aye, I was getting by just fine before. It's just in my nature to want to ensure that everything works properly, and fix it if it's not, even if I'm not going to notice the effect.

Thanks again for all the help. I'll post again sometime if I ever get it working.