Helping people with computers... one answer at a time.

There are many reasons your internet experience might slow down. We'll look at some that might not involve your machine, but rather your ISP.

Lately, I have been experiencing extreme slow down browsing the Internet. I have WinXP Home SP2 and IE7 (both up-to-date). It seems that early in the day (AM) I can browse without any problem. The PING (latency) is around +-200MS. However, later in the day, the latency increases between 1500-2500MS. This leads me to believe that there is something not right on the "network". I use cable for my Internet access. Approximately 2-3 weeks ago, the cable company relocated their equipment to a new "head-end". They also upgraded their equipment, servers, etc., to provide (supposedly) better service. Ever since this began until now my browsing experience has been mediocre at best especially later in the day and even worse in the evening hours. I have a basic idea of what latency is. But, I am wondering if the problem is my computer or not. Sometimes the slow down is so bad everything I try to (browse) "times out"; cannot be viewed. I looked at your "database" regarding latency but just didn't help me. Can you give me some help regarding this? I would be able to tell the cable peeps that it's their problem (maybe). Thanks.

I blame the cable company.

But good luck trying to convince them of that.

I also blame your neighbors, but they probably don't know any better.

Latency is nothing more than the time it takes to get a reply. That's different than the speed of your connection.

Since electricity travels at roughly the speed of light, the time it takes to get a response in the most ideal set of circumstances would be:

  • The time it takes to send a request packet at whatever your upload line speed is.

  • ... plus the time it takes for the remote server to "act" on that request.

  • ... plus the time it takes to send a response packet at whatever your download line speed is.

The problem is that there are typically several pieces of equipment between you and the remote server, and each must receive, act on, and then send the request or the response on to the next step in the communications chain.

"The most common cause for the kinds of slowdown you're describing is that one or more of the connections between devices in that chain is 'full'."

In addition, those connections aren't just carrying your requests, but also the internet traffic for others, so even in the best situations there are minor delays added as your packet of data waits for other data to be transmitted along the same connection.

The most common cause for the kinds of slowdown you're describing is that one or more of the connections between devices in that chain is "full". By that I mean that there's more data wanting to be sent than that line has the ability to keep up with. In a case like that, the devices along the way often have to receive a packet, and then wait until the connection that the packet is supposed to go out on next has room.

So what causes one of these lines to be "full"?

This is where your neighbors come in. As I said, it's not just your data on those connections.

In the morning, it might be just you and a couple of other people surfing the net and doing things. The amount of data that you're sending and requesting is, for lack of a better term, "average", and within the capacity of you cable system's infrastructure to deliver relatively quickly.

In the evening, however, things get more crowded. More neighbors come home from work and start surfing, the kids are home from school and doing their homework or playing games online. Perhaps folks are downloading larger files like YouTube videos and the like. More people making more requests using more of your cable company's infrastructure.

In addition, the sheer volume of spam being transmitted around the internet contributes, and as of late, peer-to-peer file sharing networks are also having a significant impact on the network's ability to handle other traffic.

Somewhere "upstream" from your internet connection, one of the connections that connects you and your neighbors to the internet is saturated - it's trying to carry more traffic than it has capacity.

The result is significantly increased latency. In other words, things get slow.

As I understand it, this is more common with cable internet than it is with some of the alternatives. At the "head end" you mentioned the internet connection you share with your neighbors via your cable comes together with other neighbors connected to the same head end into a single network connection back to the cable company's office. How many neighbors? Who knows? How fast is the connection between the head end and the office? Again, we don't know, but it's most certainly not big enough to handle you and all of your neighbors trying to fully use the internet at once.

In fact, as I understand it, the reason that cable tends to suffer from this more so than some other technologies is that the choke point, be it the cable you share to the head end, or the head end's own connection back to the office, is "closer" to the average cable subscriber, and thus it takes less total traffic to cause congestion.

Naturally good ISPs are continually working to keep up and improve the capacity of their infrastructure, whatever the technology might be.

Since things seem to have gotten worse when the cable company played with the head end you're connected to, it's natural that suspicion would rest squarely there.

The problem is that I can't really see a way to convince the cable company of that.

I can sympathize with their position slightly. Of the speed complaints that they probably get, the vast majority are more than likely problems with individual computers and not the internet connection itself. Viruses, spyware, old systems, and "messy" systems all slow down - and many people blame the ISP. So it's natural that the ISP would respond by saying "it's not our problem" when 99% of the time they're exactly right.

In your case, assuming everything else is the same on your machine morning and evening (i.e. your machine is basically the same in terms of programs running and the like) the fact that evenings are slower than mornings is, to me, a large indication that the problem is not your machine but rather traffic congestion upstream with your ISP.

If I were in your shoes, I would start by recording internet speed test results periodically throughout the day for a few days. If they consistently show major differences between morning and evening, and particularly if the morning results are reasonable, then I would begin hounding the cable company.

Or I'd start looking at alternative ISPs.

Article C3565 - November 15, 2008 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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16 Comments
Ron S
November 18, 2008 8:18 AM

Can this same sort of traffic congestion by neighbors happen with a DSL connection?

Yes, but it typically happens further up-stream. Rather than sharing X amount of bandwidth with a handful of neighbors, you might be sharing 10 or 100 times the bandwidth with 10 or 100 times the number of people in a much larger area. It really varies depending on the ISPs structure and capacity. As a result, it tends to happen less often.
- Leo
20-Nov-2008

Steve Keller
November 18, 2008 8:23 AM

Many blame their isp whether it is cable company or the telephone company that has dsl. The thing to remember is that it very well be out of the isp's hands. You also need a tracert to see where the problem is. It could be farther down the line on one of the major backbones. Getting a good spedd check is important also but one needs to do one that is closer to home. I and well as others us speedtest.net and use a major city closeest to me for the check. Anyone could use a distant city for the test but without a tracert to see where the request is going you would get a false test because of a trouble spot down the line.

William Purington
November 18, 2008 8:44 AM

We went through a imilar experience when the local cable company introduced internet phone service. Every time they installed a new phone in the neighborhood the cable internetservice would slow down to almost dial-up speed. They finally got it fixed and there is no problem now but for about a month they were always saying we needed a service tech call to fix "our" problem.

James Nell
November 18, 2008 11:16 AM

Another blame area is when an ISP filteres what its clients do on the internet , for example blocking certain websites , Because the filter causes a slowdown in the chain of events when sending and recieving information on the net.
BT in the uk is renowned for this kind of botleneck

Daniel Ford
November 18, 2008 4:42 PM

I believe this is just a symptom of the whole www bogging down through a failure of nodes to keep up with the massive increase in traffic from video/audio streaming and downloads. I regularly run a speed test between me and my ISP, and it's always at or above the specified speed. But browsing has become so slow over the past few months it's just no fun anymore. The 'net is dying, killed by greed!

Michael
November 18, 2008 4:53 PM

Leo .. thanks for the reply. I guess I was looking for a little "back up" so that I could say "see .. look .. it ain't me it's you"! Since initally sending question I did some checking. I did pings but just didn't give me much information to go on. In my searching about high latency, I came across PingPlotter. I downloaded the standard version (30-day trial). I ran PingPlotter and got some very interesting data to show the cable peeps that .. "see ... look ... it ain't me guys!" So, when all was said and done, I believe that I got my point across. So, for now, I just have to live with what I got and hope that the cable dudes will make steps toward "cleaning this up". Another way to look at this ... imagine a multi-lane highway. More often that not, traffic flow is ok. However, RUSH HOUR(S)!!! More traffic, some highway !!! Can you say "TRAFFIC JAM" or "BOTTLE NECK"? Anyway, again, thanks.

Philip
November 18, 2008 5:31 PM

I recently had a slow internet problem I believed was caused by my Cable co. ISP. I disabled virus software and all firewalls without any improvement. Then I started my old windows ME machine which had no speed issues.
I was about to delete and reinstall internet explorer 7 but I reset it instead. Now my machine is like new. its easy to do and you won't lose any saved favorites only passwords. I am not sure what the problem was but its been gone for two + weeks.

StevenGPT
November 19, 2008 10:46 PM

DSL can also suffer from the same Saturation problem

It took figuratively months for me to convince my DSL ISP that service really stunk from about 3PM to 9PM Monday-Friday and from 8AM to 9PM on Saturday and Sunday. How stinky? A drop from 3m service down to 175k.

Finally, after much pleading, the tech was present when the school bus arrived in the neighborhood and he document the consumption just absolutely go through the roof.

Chris
November 23, 2008 11:21 AM

Go to start -> cmd -> tracert ask-leo.com

This will show the path that your packets take on route to this website. Notice the highest latency. Now do ping ask-leo.com. Here you will see the avg ping is about the same as the highest one from the tracert. This is how you can see what part of the path is the choke point and answer questions like: does it choke when it gets to ask-leo.com's host, or early on such as maybe my router, or the early parts of the path provided by my ISP?

The way data travels through the internet is called "rout switching". If 1 path is congested, some of your packets will get "switched" to another path. In the end, packets arrive at different times, but then it's the job of the "Transmission Control Protocol/Internet Protocol" or TCP/IP to organize the data into something meaningful. It all fits into an original design, but nothing is ever perfect..

Now, where things get real messy is when you step out of your ISP's provided network and into the NAPs or Network Access Points. This is where your ISP turns its data to the routers, provided by, not your ISP, but the "free internet" where it's able to speak to other providers. My Verizon ISP can speak to someone else's Comcast ISP once it enters the NAPs. If the problem is here, there's pretty much nothing you can do about it (the internet will be slow for everyone accessing that part of the NAP).

What Leo said though, is right on the money. Most of the problems can be found in the smallest degree of the "internet" -- The nodes in the streets where the houses in your town all connect to. If they, themselves are too congested (or sometimes need maintenance), everyone in your immediate area will have a problem and this is where your ISP will notice if indeed it's only you with the issue, or everyone on your block and send a tech sparingly.

Jai
December 3, 2008 10:05 AM

hi,
well i read about your site ?
i want to ask you a thing that i am updating my windows XP from SP2 - SP3 and using IE 7 but it hangs my computer and then an error message occurs ! hence and in tast manager CPU usage comes to 100% until it comes back to normal ?

Please Help

Scott
February 9, 2009 5:53 PM

90% of the time, it's over-congested nodes. It's an industry practice to over sell their infrastructure's capability. I live in area that not only has a large teenage population as well as a perimeter of apartments that are filled with migrant laborers. 450 people on a cable node. I'm with Charter and have NEVER had worse service.

Les
June 20, 2009 8:31 PM

Actually, this is not the answer I was looking for. The connection speed I have starts out really fast, then second by second, it slows down. As each second goes by , the bytes tend to drop more and more.

zeb khan
December 30, 2009 2:46 AM

i think non of these relates to me bcoz even in the morning r evening when i want to access even the google.com site it will keep browsing and will give me the message like the server could not be accessed
and on that time when i refresh my OS then i get get no problem and every thing z going well
so i want to know what would be the problem so that to solve it and i feel get no need to refresh my OS

Paul
June 19, 2010 9:19 PM

Slowing internet speed as established above can be due to a variety of reasons, some we can control some we cannot.

I'd try something simple first like switching the modem off for a while then on again. Data gets clogged in there sometimes. Do some computer maintenance, like virus scan, clean hard disc and defrag every so often. If you have another computer it would be informative to see if there is any speed difference between them. Sometimes there are due to differences in hardware and softwares.

Hope it helps. Otherwise, well you got to change ISP I suppose.

catherine
March 4, 2013 10:28 PM

For some time I have felt that the computer slows down badly in the later hours. Tonight I decided to ask the question in the browser, and low and behold, yours was the first comment confirming my suspicions. I am extremely grateful. Thank you.

catherine
March 4, 2013 10:44 PM

This may be of some help. While waiting for the sloooow computer to make up its mind, click on to start and play solitaire. Playing while waiting is quite nice, and you can see when the page moves and then get right back on. It calms the nerves. I just discovered that 2 days ago.

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