Posted: Sat Feb 06, 2010 11:40 Post subject: WRT320N 802.11n slow performance issues
Hey all,
I searched around and read a bunch of other threads but haven't found anyone talking about this; maybe I'm missing it. I'm pulling my hair out over here. I've been using dd-wrt for various applications for 4+ years now (including OpenVPN hub/spoke deployments with multiple sites using all dd-wrt routers), so I'm not exactly new to the block here.
I've got 2x WRT320N's as well as 2x WRT54GL's, plus my laptop which uses an Intel 5100 adapter. I'm trying to mix/match them to get the fastest stable wireless speed possible. Everything is running latest DD-WRT builds as of today. Here's what I've tried:
1) Laptop 802.11n to WRT320N via either 2.4Ghz or 5Ghz, 20mhz or 40mhz channels, WPA2 AES on or off, wireless power anywhere from 40mW to 100mW, frame burst on or off. Most other settings default. No matter what settings I use, sitting 4-5 feet from the WRT320N I get 16-20Mbit/sec on file copies (2-2.5MB/sec). If I connect a cable up to the WRT320N's switchport, the same file copy from that host (also connected via cable) moves at a brisk 640Mbit (80MB/sec). But no matter what wireless setting I use, including different frequencies, my real transfer rate doesn't get better or worse; it's always in the 16-20Mbit range.
2) WRT320N to WRT320N in client bridge configuration, only 4-5 feet apart. Tried all of the same settings in #1 on the WRT320N's on either side, and tested file copies between hard-wired hosts on each end of the WRT320N's. Against, no more than 16-20Mbit/sec in either the 2.4Ghz or 5Ghz range.
3) WRT320N AP w/ WRT54GL as client bridge. Same tests and results as #2; always 16-20Mbit/sec.
In all cases, UPnP is disabled to prevent any of the high-CPU usage bugs I've read about on the WRT320N's.
I've tried nearly all of the permutations on all of the hardware (been banging my head on this since 10pm, now it's 3:30am) and have gotten nowhere.
One thing I will mention: I have a 3rd WRT320N running the latest stock Linksys firmware, but I'm about to RMA it because it crashes constantly (gets way hotter than the other 320N's, so I think it overheats within 5 minutes or so of boot). However, running the stock Linksys firmware on this thing connected 5Ghz/40Mhz from my laptop, I'm able to get 50+Mbit for a short time until the thing crashes.
Am I missing something? Is there a big billboard somewhere that says DD-WRT is limited to 20Mbit throughput on this hardware? I expected much, much more. I figured to solve the issue I'd stick all of the hardware in the same room, reset all factory defaults, and disable encryption to the best possible results and then move out from there, but no dice!
Joined: 13 Nov 2008 Posts: 5266 Location: CENTRAL Midnowhere
Posted: Sat Feb 06, 2010 13:49 Post subject:
20mbs is good if you are not in N only mode. If you want faster throughput, you have to go to n only and proper settings. I think/hope there is a wiki article on N settings. But you won't get any faster than that if anything is g or mixed mode.
So, you won't get any faster if you have those GLs in the mix. I am surprised you were able to get 20mbs if those were there.
You also obviously haven't read the announcements if you are talking about "latest build".... _________________ Warning: I'm "out of my element!"
http://www.youtube.com/watch?v=MjYJ7zZ9BRw&NR=1
Ugh, I love when a forum lists 6+ pages of posting rules and then members poke at you for missing a single request in those rules, despite the rest of your post being plenty detailed. Anyway...
On my WRT320N's, I've tried running at least 13491 and 13297 for last night's tests, but have run several other builds I cant' remember over the last couple of months when troubleshooting this issue.
On my WRT54GL's, I've tried running 13064 (latest) most recently for the purposes of my specific tests last night, but like the WRT320N's I've tried other builds as well.
Also, yes, I've checked the 802.11n Wiki page at http://www.dd-wrt.com/wiki/index.php/Wireless-N_Configuration before posting. I always read as much detail as I can find in the forums before posting (spent hours last night), and only post as a last resort when I'm at my wit's end.
I have *definitely* tried N-only modes in the 2.4Ghz and 5Ghz bands (N-only and NA-only, respectively) with the WRT320N's, and only threw in testing with the WRT54GL's to compare performance, which seems to be identical to the WRT320N's in N-only modes.
To be specific (though I think my original posting laid this out): I've tried using just the WRT320N's as high as 5Ghz, 40Mhz wide, with and without WPA2 Personal AES encryption. I've tried connecting my laptop's Intel 5100 directly to the main AP in 5Ghz 40Mhz mode, and I've tried hard-wiring my laptop to the second WRT320N in client bridge mode. In all cases, no matter my configuration, with all equipment no more than 5 feet away, I cannot get speeds faster than 20Mbit/sec.
Finally, to be clear about how I'm testing: I have a file server wired to the main WRT320N. In all cases I attempt an FTP file transfer, both up and down. When I'm wired to the main WRT320N with the file server (no wireless involved), I get 600Mbit/sec+ file transfer rates (80MB/sec). That's my control to know that the file server (RAID controller) and my laptop (SSD) can deliver much higher speeds than I'm seeing over wireless. Again, in no configuration I've tested with wireless involved, have any of my FTP tests passed 20Mbit/sec.
I did try turning WMM off, but my laptop won't connect to the main AP in 5Ghz/40Mhz without it.
If anyone has any constructive input, I've love to hear it.
Joined: 13 Nov 2008 Posts: 5266 Location: CENTRAL Midnowhere
Posted: Sat Feb 06, 2010 19:48 Post subject:
ryanjwh wrote:
Ugh, I love when a forum lists 6+ pages of posting rules and then members poke at you for missing a single request in those rules,
There are not 6+ pages of rules, the information you missed was the single essential most important piece of info, without which no one can assist in a meaningful way. Which is why it is the sole information in red in the announcements. 13064 is NOT the latest build and is not even a good build. If you are using that build and post it as latest, you STILL haven't really read the announcements. Have you missed doing proper hard resets too?
If you want N speeds, you have to stick only to N connections and not throw any G red herrings into the mix. With G connections you can expect the results you have experienced. You are dealing with extremely new, experimental builds that continue to have issues and throughput in N on that router might be one of them. There are many, many posts on correct settings to keep N speeds, and putting routers 5 feet apart will decrease performance. They need to be separated by much a greater difference to avoid signal interference. Get your connection speed to show in the webgui at 135+mbs and then test. _________________ Warning: I'm "out of my element!"
http://www.youtube.com/watch?v=MjYJ7zZ9BRw&NR=1
Actually, if you go to the download page and type WRT54GL, 13064 is the latest down for that model. I also demonstrated that I'm running a much newer build on the WRT320N's.
My point about six pages was that the first reply stated I needed to read all of the announcements before posting, and all totaled there are about 6 pages worth at least.
In any case, as for distance, I should clarify: I only put the hardware 5 feet apart when I didn't know what else to try. I have tried them 5, 10, 20 feet aprt with walls and no walls, and I get the same results regardless. It's as if something is hardware limiting me, and by using wired to a bridge I've ruled out my laptop.
I came to this forum for help, as that's one of the main reasons it exists. Can anyone share if they're able to demonstrate greater than 20mbit/sec sustained throughput on a WRT320N? If so, what settings are you using? I listed above what mine were and I've had no luck
Yes, I'm doing resets. I always do. This was harder to do back before Eko found a way to fix Linksys's design error on the reset button on the WRT320N, but now thanks to him we can use the WPS button :)
Second, let's just pretend the WRT54G's don't exist. Most of my testing was N-only with just my laptop and the WRT320N's. The WRT54G's weren't used (or even powered) until I was at my rope and wanted some comparison.

I'm seeing the same performance issues in 2.4GHz N-only mode, using 20 MHz channels - 5 GHz performance is abysmal. I don't really think it's a problem with the WRT54Gs being on the network.
Joined: 13 Nov 2008 Posts: 5266 Location: CENTRAL Midnowhere
Posted: Sat Feb 06, 2010 22:30 Post subject:
I don't have the router, and perhaps someone who does has figured out setting that work and will post them. However, until then, go to the status/wireless page and look for the "rate" information. Focus on getting that number above 100. That is your connection speed. If it is above 100, then you are working in N mode. You need to use WPA2-aes to get that connection speed. Search the forum for other settings if you can't get it established. Some have suggested wide channel is needed. All of this should be in the wiki but it is still a work in progress. Real N support is still relatively new.
Then, once you have that tweaked and connected at a proper N speed, check your actual throughput by testing it as you have been. Use the throughput graphs in the gui.
13064 is dd-wrt recommended, but there are much better builds. That router database has some bad advice. It is not as obvious as it might seem. The other recommended so called stable build is SP1, which is shite. Once you have been around here longer you will understand. It is easy to become confused. Which is why it is so important to read the announcements in this forum as they clarify things. _________________ Warning: I'm "out of my element!"
http://www.youtube.com/watch?v=MjYJ7zZ9BRw&NR=1
I don't have the router, and perhaps someone who does has figured out setting that work and will post them. However, until then, go to the status/wireless page and look for the "rate" information. Focus on getting that number above 100. That is your connection speed. If it is above 100, then you are working in N mode. You need to use WPA2-aes to get that connection speed. Search the forum for other settings if you can't get it established. Some have suggested wide channel is needed. All of this should be in the wiki but it is still a work in progress. Real N support is still relatively new.
Then, once you have that tweaked and connected at a proper N speed, check your actual throughput by testing it as you have been. Use the throughput graphs in the gui.
13064 is dd-wrt recommended, but there are much better builds. That router database has some bad advice. It is not as obvious as it might seem. The other recommended so called stable build is SP1, which is shite. Once you have been around here longer you will understand. It is easy to become confused. Which is why it is so important to read the announcements in this forum as they clarify things.
I'm well aware of this (I suspect ryanjwh is as well) - even when the wireless rate is above 100, actual throughput is much slower than it should be. I've tried almost every build that the WRT320N supports (currently using 13637) and the results are almost unchanged between builds, save for a few fixes for uPnP and whatnot.
Also, I might have recently registered, but I've been using DD-WRT for almost 3 years now the standard "read the stickied threads/announcements" reply has been basically beaten to death at this point and frankly comes across as a little pompous, particularly when it's been stated multiple times that yes, they've already been read, and no, they're not helpful (at least not in this regard).
Joined: 13 Nov 2008 Posts: 5266 Location: CENTRAL Midnowhere
Posted: Sat Feb 06, 2010 23:27 Post subject:
amf5 wrote:
Also, I might have recently registered, but I've been using DD-WRT for almost 3 years now the standard "read the stickied threads/announcements" reply has been basically beaten to death at this point and frankly comes across as a little pompous, particularly when it's been stated multiple times that yes, they've already been read, and no, they're not helpful (at least not in this regard).
Then answer his question.
And feel free to deal with any of the other standard issues that come up repeatedly in daily posts that are already dealt with in the announcements before I tell people to read them. Like failing to state build number, and continuing to use less stable builds like 13064.
If you don't like how others respond, respond yourself. Sitting back and critiquing is easy. No one is stopping you from doing a 'better' job... the way you seem to think others should do things.