WNDR3700v1 wireless throughput half of DIR-825

[Ascaris5]

Hi,

First, am I remembering correctly when I think there used to be a dedicated subforum for the 3700?  If it is here, I don't see it.  It's been years, though; I have had this router a long time, as I bought this v1 when that was all there was.

I am connecting to the 3700 with an equally old laptop, which has an Intel 4965agn wireless card.  My main PC (much more current) is attached via ethernet cable, and I have taken some spare parts and put together another PC to act as a NAS for the purposes of backing up the laptop and the main PC, also connected with an ethernet cable.

The sorta-NAS works very well with the wired connection, and wired throughput exceeds 100MB/sec copying a large file as reported by Windows, so no complaints there.  Unfortunately, though, I have run into issues with the laptop when connected wirelessly.  As both the laptop and the router are capable of operating in the A band, I use that exclusively to avoid interference with the ten or so APs my neighbors have in use in the G band.  I have the entire A band to myself!

When the laptop connects to the 3700, it reports 300 mbps as the connection speed (though it fluctuates a lot).  The router is about 12 feet from the laptop, with no walls in between, and signal strength is usually 5 of 5 bars, though it sometimes shows 4.  The actual speed copying a large file from the laptop to the sorta-NAS wirelessly ranges from 6 to 8 MBps.

While I was troubleshooting an intermittent connectivity issue with the laptop and its 4965agn to the 3700 (which seemed exactly like the "Sporadic Wireless Disconnects Caused by Data Reordering Issue" as reported by Intel with their wireless drivers [five years after the last driver for the 4965 was released, so I don't know if it really is the same issue, but the symptoms AND the workaround of turning off N mode both apply]), I read that the issue was happening for sure with Netgear routers/APs, but not some others. I know it's not all in the router, as when the disconnects come, rebooting the router won't bring the connection back, but rebooting the laptop will.

I dug out my old D-Link DIR-825 and tried it.

I was surprised to find that with the same reported connect speed of 300mbps (with the same fluctuations), I was getting actual file copy speeds of exactly double what I had gotten on the 3700-- 12 to 16 MBps.

Both routers use the same encryption (AES) and the same 64-bit string of hex characters as a key, so if anything, the much slower D-Link should be lagging behind, but it's not.  Not only that, but the wireless connectivity issue has not happened with the D-Link (it may at some point, as that is the nature of intermittent issues, but it has been a long time on the D-Link).

The 3700 is a much faster device, and all of the tests of the 3700 vs the DIR-825 (when both were new and in their first revisions) mention that the 3700 outperforms the D-Link by a large margin, but that is certainly not what I am seeing now. 

I am using the latest official firmware for the 3700 (1.0.16.98).

Any ideas on what I can do to get the 3700 up to speed?  I know there used to be a lot of messages about the poor quality of the firmware for the 3700v1... but like so many manufacturers, Netgear seems to have forgotten about older products that are still quite usable (and in this case, still being sold, even if they are in the fifth or higher revision).  Should I be investigating alternative firmwares?

Thanks!

[doraemon · Accepted solution]

Then it's definitely a hardware failure.

[doraemon]

Looks like it's starting to fail.

3rd party firmware may help if after reloading the latest firmware didn't fix it. 

[Ascaris5]

I've only had one router fail before (although I currently own 5), and it just stopped working one day-- no lights, no anything.  Is this the usual way they fail if they don't just suddenly die?

I flashed the WNDR3700 to DD-WRT, and the wireless speed was even lower than with the stock firmware (about 3 MB/s).  I messed with the settings all I could, but I could not get it going any faster.  With that in mind, I went back to the stock firmware using the router's recovery mode, and it worked... but the speed was still 3MB/sec.

It does look like its giving all it's got.  Even with excellent signal strength and 300mbps connect speed, it's slow.  It's even slower in the b/g band, which probably has something to do with all of the other APs using that band around here.

The D-Link is actually working pretty well so far.  I don't remember why I switched from it to the 3700; I know the 3700's cpu is about twice as fast, but I can't remember what I was doing (if anything) where that mattered.  Or maybe it was unreliable... I don't remember. I've been using the Netgear for a long time!

I do find the onboard setup utility to be needlessly confusing compared to the Netgear version, and the constant logging me out while I am changing settings (and not accepting the changes as a result) is infuriating... but it is much faster than the 3700 on wireless and just as fast on gigabit wired.

[doraemon · Accepted solution]

Then it's definitely a hardware failure.

[Ascaris5]

I think you're right. 

I opened the WNDR3700 up... look at these capacitors:

Only one of the four is not visibly bulged. 

Ltec caps, Netgear, really?  A quality router needs quality parts!

Looks straightforward enough to replace them, though.

[doraemon]

Are you going to replace those capacitors? Give an update after.

Good luck!

[Ascaris5]

That's the plan!  I ordered the new capacitors today, so they should be here within a week or so.  Thanks for pointing me toward hardware-- I was focused so much on the often-buggy firmware that I could not see the forest for the trees.  Once I was thinking hardware, my mind immediately went to capacitors-- that was why I opened the unit.  I don't think there is anything else I would be able to diagnose or fix inside the unit. 

What a pain cheap capacitors are.  I also have a Cooler Master PSU and an LG Flatron monitor that have partly or totally failed, and upon inspection were found to have bulged capacitors.  The PSU is not really worth fixing as it was a lower efficiency unit without PFC anyway, but I will also try to fix the monitor (I ordered the parts for it too).  The people over at badcaps.net are helpful for all kinds of capacitor issues.  

The four caps for the 3700 and the five for the monitor, in premium quality items with low ESR, cost under six dollars, and that's the retail price for a very small number of them.  It would have been a lot less for Netgear or LG to buy those instead of the Ltec and Su'scon caps, and the devices would last longer and make for happier customers.  Sure, they made it past warranty, but customers expect to be able to use things they buy longer than that, and having an item die on them before they think it should have makes it more likely they won't buy that brand in the future.  Since capacitors are the most likely (as far as I can tell) components to fail from normal use of a properly-designed electronic device, does it really save money in the long term to use cheapo caps rather than good ones? 

I know when I was in the market for a new PSU (active-PFC, gold or better efficiency, modular), it was top-tier caps across the board or nothing.  Inspecting the capacitors and other components in a  PSU is the norm for all of the good tech sites that do reviews on them, but that level of attention has not filtered down to reviewers of things like routers, unfortunately.  If top tier (Japanese, usually) capacitors were a selling point as they are for PSUs, motherboards, etc., I am sure Netgear would have used them. I'd bet that all of the other consumer router makers use cheapo caps too; this is not a Netgear thing.  It's a consumer electronics thing.

I will post again after the replacement is done!

[doraemon]

I'm excited to know the outcome! 

[Ascaris5]

It worked!

I got the new caps today and put them in.  It was easier than I expected, but I definitely need a desoldering iron or solder sucker. 

As soon as I got it all put together, it started right up, and when I tested the wireless speed, it was back up to where it should have been, ranging from 13 to 15 MB/s for the transfer of a 4 GB file. 

Now I just get to worry that I somehow messed something up and it will fail again, but there's nothing I'm aware of that I messed up. 

Here is a pic of the new caps installed:

[Ascaris5]

...and it was well worth the effort, too; the DIR-825 can't compete with the WNDR3700. I know these are old routers, but the 3700 is AFAIK still in production in its fifth or so revision, and the D-Link was only recently EOL'd, so maybe it's still relevant to someone other than me.

I tried using an online game, one that I had QOS and WISH rules set for maximum priority, in the DIR-825. I then sent a large file (4 gb) from my laptop wirelessly to my sorta-NAS PC while I watched the latency on my main PC (so three PCs total involved here). The file copy only affected the main PC insofar as it was loading the router and testing its ability to route packets from WAN to that PC while loaded.

The latency in the game went up and up (it's an average latency over some period of time displayed in game), causing a noticeable lag in the game. This is precisely the kind of thing QoS is supposed to prevent, but it was happening anyway, even though I had QoS on and WISH on in the D-Link. VOIP would have also been affected negatively.

I tried disabling WISH but leaving QoS on; I tried putting QoS on and WISH off; I tried putting them both off. I tried changing QOS settings. Some attempts were worse than others, but all of them increased latency at least 300 ms beyond the usual. And that's with the router only having to handle 15 MB/s or so, well below the 100MB/s of gigabit to gigabit transfers, although the wired connection would not have to process the WPA2-AES encryption either.

After the new caps were put in, I tried it on the (again fully functioning) 3700. The entire file copied without even 1 ms increase in latency in game. Not even the slightest hint that something was happening could be seen in game.

I know the WNDR3700 has twice the clock rate in its Atheros CPU as compared to the Ubicom in the DIR-825 A1 (no idea how they compete in instructions per cycle; I could not find any info about that)... but the B revision of the 825 has the same CPU and clock rate as the 3700, and according to benchmarks, the 3700 still stomps it in throughput. I have no idea why-- I cannot imagine that the firmware on the D-link would be SO bad as to harm the performance that much, but who knows? At least the rev B can use the same DD-WRT as the 3700, which may improve performance. The A1, with its Ubicom cpu, cannot accept any alternative firmware that I know about, so the performance I described was all I was going to get.

I have thought about putting DD-WRT on my 3700 (again), but it is working so well... why fix what is not broken? Until there is some feature I want that is not in the stock firmware, or until I discover a bug that affects me, I can't think of a good reason to do that.

[doraemon]

That's awesome! 

It cost you so much less than buying another brand new one.