I have been given a 1 month free trial of a 35Mb/s internet connection.
(This will cost 6.99 euros/month extra if I keep it).

Up to now I had a 15 Mb/s connection and could achieve 12 -13.

Now, a Windows XP machine (single core 3.0 GHz Intel CPU) is getting 32Mb/s.

Two Linux machines, one a 4 core, the other, 2-core both with AMD CPUs can only get 20Mb/s.

This is using the same cable, ADSL modem etc. The only variable is the PC.

My question(s): Is this a known phenomenon? Is it Linux or AMD? Is there a fix?

I doubt that I will keep this "High Speed Connection". Most of our browsing is to foreign sites and speed are limited by the undersea link to the rest of the world. Nevertheless I'd like to get to the bottom of this.

Could it be that the on-board ethernet hardware is not up to the job? Settings are 100Mb/s, Full Duplex.

Boot to a BartsPE or UBCD4win cd maybe.


I'd look at a few things.
One is systems loads.
Look at cpu loads.
Look at nic settings for checksum offload or if possible.
Yes cheap nics can suck up resources. Cheap drivers for nics can too.
Might look also at filesystem. Drive could cause bottleneck.
Ram usage or even swap file could be an issue.

Maybe 20 other things.

Thanks Jefro,

Lots of food for thought.

You left out magic

Today I got 35 Mb/s on the Linux PCs and 26 on the Windows one!

This was just before starting to look for a 100Mb NIC - I'm sure I have some around - to use instead of the on board ones.

Ah well, I'll just have to keep watching the situation.

Thanks again.

Hi,

One other thing to take into consideration would be interconnections. Do you have any switches or hubs? Proper specs for the devices selected? Cable type, Cat 5/5e/6 Article and distance to the modem? You need to find the weak points within your LAN to get things to peak performance by making corrections when needed. Some useful links;Hope this helps.
Have fun & enjoy!

Thanks for this. I have found a couple of dodgy plugs in the system but they do not seem to be the problem.

The test I reported bypassed hubs and switches and was simply one PC connected to the ADSL router via a 20m Cat 5e cable. (The same cable in each case).

Play proceeds.....

I have read that internet data rates on cable TV networks are sometimes limited by what your neighbors are doing. If everyone is downloading movies at the same time, it slows down. To investigate this, you could measure the speed at different times of the day and night.

What kind of speeds do you see between computers on your home network? If it too is 20-35 Mb/s, it could be that the bottleneck is between your computer and the router, not on the internet side.

It sounds like you are getting close to the advertised 35 Mb/s rate. What more do you want, or what do you want to know? If you are just curious, that's all right.

The Windows PC came close enough to 35 Mb/s. My question related to the Linux PCs which failed to get close.

In each case the tests were carried out within minutes of each other, using the same 20m cat 5e cable and connecting the PCs directly to the same socket on the router.

The only variable was the computer. All three have totally different hardware. One runs Win XP, the other two run Debian Unstable.

I now want to try cleaning the RJ45 sockets. After that I will try a PCI NIC rather than the onboard one.

Hi,

For Wondows, my ISP suggests the following registry settings:
https://support-en.upc-cablecom.ch/a...ower-optimizer

For linux, I could double the effective bandwodth from 12 to 24 Mbit/s on a cheap realtek based 100M bit/s card by increasing the buffersize in the driver.
Make sure that at least two packets fit into the buffer (3 kBytes).

Interrupt latency is the main problem. Make sure you get a card that handles several packets per interrupt. Onboard HW is often too cheap.

Good luck.

I seem to have cleared up the problem.

The Windows PC was delivering the speed so the problem(s) were on the Linux side.

1. Replaced 3 RJ45 plugs which had broken clips. Seems that they made contact, but no firmly enough.
2. Replaced a section of cable which might have been pinched at some time.
3. Discovered that sometimes Bittorrent, although not moving much data, exerts an inordinate bad influence on the network. So ensure it is not running when I test speeds.

It is interesting to note that the advertised bit rate is only a part of the story. Within Malta I get 30-35Mb/s. On European sites I get 4-7Mb/s. On American sites I get 3-5Mb/s.

So the limiting factor seems to be the Internet backbone and paying for high bitrates is probably a waste of money.

Thanks for the inputs.

Hi,

Yes, you need to be sure not to crimp or bend the radius of the cable beyond specs. If you are using CAT 6, be sure not to pull cable ties to tight as this can create problems for speed. Threat your cable with care if you want the peak performance from them. For any specified cable be it 5/5e/6 you should be careful how you mount the cable. I like to use cable plates/mount/clips(w/nails where applicable) that have a specified dimension. Be sure not to use 5/5e mounts on CAT 6 cable since the CAT 6 cable is thicker than '5' cables. When permanently mounting cables, fix point mounts should be about 5 feet between mounts, if you are mounting more than one cable with a single J hook make sure that the spacing between mounts is not uniform. When possible place the mounts at a usable but not repeating space points between mounts. This is true for copper that can cause issues with signal injections with repeated same fixed points.

Treat the cable tenderly when making fixed point mountings. One reason to use cable trays or hooks if possible. Sure more $$ but worth it if you want a good LAN.

I have seen some so called professional LAN installs that are nightmares. Pretty but not practical and following good cable placement techniques.

Radius support(simple plastic formed carrier) in a wall that is to be closed are very important since the weight of the cable can bend tight with the weight of the cable pulling down on a cable placed in a through hole thus causing a tight radius that cannot be corrected once the wall is closed. That $0.25/ea is worth the investment. I have used twisted spiral cut spaghetti wrapped around a cable that is going through a hole to insure no bend caused by weight then mounting a fixed mount below the hole over the spaghetti wrap(not tight here either). Cheap means to support single cables in a wall where the line must drop down for placement of a terminal/RJ45 box mount.

Do not place a rug over a LAN cable that will have traffic. They make small floor raceways for moving cable between points of this sort that are placed on the floor preventing the step onto a cable thus flattening the pairs. Treat your LAN cables as if the cable was a water hose, sharp bends choke the flow through the hose. The same with a cable, bend to sharply and you will attenuate the signal because the diameter has changed electrical characteristics.

Good 5e tutorial.

Do it right or do not do it!
Hope this helps.
Have fun & enjoy!

The cable in question passed through a bedroom, behind the bed, but I never got around to installing trunking. Somebody placed the bed leg on the cable.