Mysterious network speed cap on my PC

November 19, 2007 7:06 PM

There is a mysterious network cap somewhere on my PC, tried everything I know.

Okay, so I changed ISP recently because I couldn't seem to get above a 1MB connection. I switched to Qwest 7MBs line, and I still can't seem to get any higher then 1MBs. Here's the odd thing, I installed a PCI Gigabit ethernet card and all of the sudden I am gettting 2MBs, but no more.

I have an ASUS m2npv-vm mobo that uses the Nvidia nForce 430 chipset with gigabit lan and also hooked up a Rosewill (Realtek chipset) PCI gigabit lan. I have uninstalled/reinstalled the drivers numerous times, and reset all BIOS settings to default. I am having the same cap on all web browers and my utorrent application. Any help would be appreciated.

posted by lattiboy to computers & internet (21 comments total)

What's your local network setup like?
posted by Oktober at 7:16 PM on November 19, 2007

How are you testing the speed of your connection? Have you looked into issues (age, condition, interference) with your phone lines?
posted by bonobo at 7:18 PM on November 19, 2007

I wonder if you might be confused.

My network connection with Comcast is 8 megabits per second. That's about 900 kilobytes per second when it's maxed out (because of overhead).

I've never heard of anyone offering 8 megabytes per second for home service. That would be in excess of 70 megabits.
posted by Steven C. Den Beste at 7:21 PM on November 19, 2007

Another point: the only server I've ever talked to which will max out my line is Microsoft Update. Everything else places a cap on their outgoing data rate which is well below what I can support with my line.
posted by Steven C. Den Beste at 7:26 PM on November 19, 2007

run SpeedTest and let us know what you get
posted by Oktober at 7:42 PM on November 19, 2007

Try testing against I2 Test Sites. You won't have to worry about maxing out the server... The software is also pretty good at diagnosing some common problems.

Where are you trying to send/get your data? Distance (ping time) can wreak havok on your speeds. Try another cable between your computer and the cable modem... (don't laugh, that's the problem like 5% of the time or so). Can you test between 2 machines at your home?

It's probably not drivers or anything like that, you're at less than 10Mb/s which is ancient technology. Worry about drivers when you can't get above 500Mb/s on a 1Gb/s local connection.
posted by zengargoyle at 7:48 PM on November 19, 2007

Thanks for the quick responses. I am aware of the MB vs. MBs. I'm capping out at around 100kbs download. I've tested on Speakeasy.net (on the local Seattle server) and speedtest.net . I've tested these previously (when I had Comcast) and got 10 MBs quite regularly. I am connected directly into the modem. I had the same issues on DSL and cable, so I don't think it could be interference. I'm totally puzzled. I ran it by our network admin and he couldn't really think of an issue either. Could this possibly be some kind of hardware issue with data flow? Its happening less on PCI then on the ethernet controller. I'm about 1 day away from a full reinstall of windows.
posted by lattiboy at 7:57 PM on November 19, 2007

I had a 1.5Mbps DSL line with Qwest and later upgraded to their 7Mbps. I had the same symptons as you after two weeks with the new cap. When I called Qwest tech support, it turns out they hadn't actually 'flipped the switch' over to 7Mbps. Once they changed their setting, the switchover was instantaneous. Now I get 700KBps downloads.
posted by phrayzee at 8:08 PM on November 19, 2007

Just in case, Qwest contact numbers
posted by phrayzee at 8:09 PM on November 19, 2007

Thanks for the quick responses. I am aware of the MB vs. MBs.

So are you actually getting 2 Mb (mega bits per second) or 2 MB (Mega Bytes per second)?
posted by bitdamaged at 8:11 PM on November 19, 2007

Little b == bits. Big B == bytes. 8 bits == 1 byte.

Unless Quest is offering the equivalent of an OC-1 connection to their users, I highly, highly doubt you're supposed to get 8 MB/s. To put things in perspective, USB 1.1 connections are 12 MB/s. If you're Stateside, you're more likely anticipating 8Mb/s.

Unless there was something wrong with your old network card, there was no reason to upgrade to gigabit bandwidth. Your network speed is only as fast as the slowest link. Placing a gigabit network card in your computer is like building a 10-lane highway between two towns that are a mile apart and only have ten people living in either of them. In other words: complete overkill.

You could use an old 10/100 network card and you still wouldn't saturate it.

Another point: the only server I've ever talked to which will max out my line is Microsoft Update.

My USENET server can easily saturate my bandwidth. Thing is, most ISPs will shape the traffic on their network to favor web connections over other transport methods (bittorrent in particular). You can encrypt your connection (most clients do this by default these days) but the packets are still identifiable as bittorrent, even if the actual contents are encrypted.

My recommendation to the OP: if you're trying to improve your download speeds, stop using bittorrent and switch to a protocol ISPs aren't actively limiting.
posted by Civil_Disobedient at 8:37 PM on November 19, 2007

Its worth knowing that just because some sells you 7mbit service does not mean you get 7 megabits per second. You get whatever speed your DSL modem is programed to negotiate. In my neighborhood thats 1.5mbps. No one gets higher thn that because we are so far from the CO. AT&T sold me 3mbps service but I still could only handle 1.5 fwiw.

This: "I've tested these previously (when I had Comcast) and got 10 MBs quite regularly" suggests to me that this is a DSL limitation.

Your next troubleshooting step is to borrow a laptop and see if it gets full speed on your network. If so then you'll know its a local computer issue.
posted by damn dirty ape at 8:48 PM on November 19, 2007

Also ask here: dslreports.com. Thats where the DSL experts live.
posted by damn dirty ape at 8:53 PM on November 19, 2007

*cough* *cough*. Choose your ports wisely and block RST packets wisely.

Rough time tested benchmark, 10 Mb/s == 1 MB/s... overhead included, a 10 bps == 1 Bps. Never underestimate the power of a seemingly minor transmission error along your path. A one in a billion error rate will keep your TCP transmission at half or quarter speed. Never underestimate the fact that Windows networking stack sucks balls. Two Linux machines on either end will get %50 faster transmission speeds. Two 'tuned' Linux machines will get %150 better transmission speeds. Windows TCP network stack sucks balls.

OP still confuses me by not differentiatiing between Mb/s and MB/s.
posted by zengargoyle at 9:04 PM on November 19, 2007

Borrow someone else's PC and check that. Also check with a Mac or Linux box (in case it is Windows specific). If those boxes are also slow, then it's your ISP and you need to have a chat regarding how much you're paying vs. what you actually get.
posted by TeatimeGrommit at 9:20 PM on November 19, 2007

Again, thanks for all the responses. I checked the modem interface and it shows:

Downstream Rate: 7168 Kbps

Upstream Rate: 896 Kbps

Which is what I'm paying for. Sorry for the confusion re: little b, big B. My bad, I was rather busy when typing this. I am aware that the gig card is overkill, but it was the only one I had on hand. I don't have another PC to test transfer rates with, so I don't know how else to test this. I'm going to boot into Linux and see if it is Windows specific (should have thought of that myself)....
posted by lattiboy at 10:20 PM on November 19, 2007

Okay, so it IS a hardware issue. I booted into Ubuntu 7.10 and went to both Nvidia and Microsoft download center (never got less then 500kbs with Comcast on those) still stuck at right around 100 - 120 kbs. Ugh. I really hope I don't have to replace my mobo.....
posted by lattiboy at 10:30 PM on November 19, 2007

I highly doubt the issue is with your NIC.

Have you tried connecting to another PC and seeing what speeds you get copying files over the local network? That would be my first test.
posted by mphuie at 12:51 AM on November 20, 2007

Before doing a Windows re-install, it might be good to check some current registry control values for your TCP/IP stack. Here's a decent tutorial. Next, you might want to see what kind of processor utilization you're experiencing under maximum network loads (some driver issues become apparent as excessive processor loading), by pulling up Task Manager and seeing how your processor is getting along. If you see high utilization, and for XP Pro only, type

tasklist /svc

in a Command Line window, to get a list of services bound to processes. Investigate any services that seem suspicious.
posted by paulsc at 5:49 AM on November 20, 2007 [1 favorite]

before you start swapping out parts, call your ISP

this sounds like an "oops" on their part
posted by Oktober at 6:11 AM on November 20, 2007

Okay, so it IS a hardware issue. I booted into Ubuntu 7.10 and went to both Nvidia and Microsoft download center [...] still stuck at right around 100 - 120 kbs.

Your deductive reasoning needs polish.

All you have successfully proved is that it is not an operating system issue. That could mean a bad NIC, or it could mean a bad network cable, or it could mean your provider is overstating their bandwidth.

Given a choice between those three options, I would pick "ISP Fucking With You" every time primarily because electrical components normally either work or don't work. It's extremely rare that something would work with 100% functionality but at 10% of its rated speed, unless whatever it was that was failing had built-in redundancy.
posted by Civil_Disobedient at 5:02 AM on November 21, 2007