Download speed slow on one computer

[ajdornier]

We have signed up for a 100 mb download / 10 my upload service with our ISP. Their modem is a Hiltron CGN3 which I've configured to function as a modem only (wireless was crappy IMHO) and hooked it up to my Cisco E4200 with a CAT 5 cable. Two computers are connected via CAT5 cables to the E4200.

For some reason one computer only shows as having 20-24 mb as download speed using speedtest.net while the other computer consistently shows over 100. Both show 10 mb consistently as the upload speed.

We've tried the following:
- hooked the slow computer directly to the modem. It showed 100mb in the test. After hooking it up back to the router, it showed slow results again. Therefore we ruled out faulty cable as well as PC config issues.
- switched the ports on the router between the two computers. The slow one still remained slow and the fast one remained fast. We therefore ruled out router issues.
- switched off antivirus on the slow computer. No change.
- rebooted in safe mode with networking. No change.
- replaced the cable between router and modem. No change.
- searched for the AMD quickstream program. Couldnt find it.

We're officially stumped. If something was up with the PC configuration, then hooking it up directly to the modem wouldn't have made a difference. But if it was a router issue, then the slow computer would've become fast and vice versa when we switched their ports around.

Any help would be appreciated...thanks!

 

[Ralston18]

Some suggestions:

Double check and compare the network adapter configurations between the computers.

Compare the ipconfig /all results between the slow and fast computers while both are up and running.

Then ping the router from both computers.

See if you can spot any differences or unexpected settings.

 

[ajdornier]

Some suggestions:

Double check and compare the network adapter configurations between the computers.

Compare the ipconfig /all results between the slow and fast computers while both are up and running.

Then ping the router from both computers.

See if you can spot any differences or unexpected settings.

Thanks for the suggestions! I tried them all and we couldn't spot any differences (other than the make/model of the network adapters and the IPv4 and v6 addresses of each computer). Pinging yielded identical results as well.

 

[Ralston18]

Very helpful in that that excludes some possibilities.

Not sure where to go from here but I am going to fall back on the first thing you tried: i.e., hooking the slow computer to the modem and then getting the full 100 mb.

If the slowness problem only occurs with the router in the path and independent of the router LAN port being used then that suggests to me that the router is indeed likely to be the culprit. Specifically there is some configuration parameter that is limiting the "slow" computer.

Go into the E4200 admin pages and look at the QoS settings. Look for any settings that change network priorities or limits. Especially if you can associate that setting with the "slow" computer. Maybe the MAC or even the IP address.

Consider trying another router if you have one or borrow a router from someone. See if the problem replicates.

Failing anything there, I would do a factory reset on the the existing E4200 router and just reconfigure it from scratch.

Post accordingly and maybe someone else in the forum will spot something further.

 

[ajdornier]

Very helpful in that that excludes some possibilities.

Not sure where to go from here but I am going to fall back on the first thing you tried: i.e., hooking the slow computer to the modem and then getting the full 100 mb.

If the slowness problem only occurs with the router in the path and independent of the router LAN port being used then that suggests to me that the router is indeed likely to be the culprit. Specifically there is some configuration parameter that is limiting the "slow" computer.

Go into the E4200 admin pages and look at the QoS settings. Look for any settings that change network priorities or limits. Especially if you can associate that setting with the "slow" computer. Maybe the MAC or even the IP address.

Consider trying another router if you have one or borrow a router from someone. See if the problem replicates.

Failing anything there, I would do a factory reset on the the existing E4200 router and just reconfigure it from scratch.

Post accordingly and maybe someone else in the forum will spot something further.

Hi -

I tried the above and there was nothing specific in the QoS settings (or anywhere else for that matter) for either computer. I went ahead and did the factory reset on the E4200 and left everything at default.

When I hooked the two computers up, it was still the same thing (i.e. the "slow" computer remained slower than the other one). One thing I did notice though...when I checked the port status on the E4200, the Internet Port Speed was 1Gbps, and so was the port where the "fast" computer is on. The "slow" computer was reporting 10/100 Mbps. Wondering if this was an indication of something on my network adapter, although it wouldn't make sense if it went "fast" if I hooked it up to my ISP's modem.

I re-compared the settings on the network adapter between the fast and slow computers, and the settings were the same, although the fast computer's adapter settings had more options (like IPv4 upchecking and such). The "slow" computer's network adapter is an NVIDIA nForce Networking Controller. When I checked the speed on it via the Local Area Connection Status, it's reporting as 100 MBps...same as the "fast" computer.

 

[ajdornier]

Update: I was out and about and decided to buy a $12 D-Link gigabit network card. I plugged it into the "slow" computer and voila! the speed is as it should be. This solves my problem (thanks Ralston18 for all your help) but still leaves the question as to why the onboard NIC would have behaved one way connected to the ISP modem and another connected to the E4200. I would consider my problem solved but if someone else can provide insight into the mystery above then it might help others out.

 

[Ralston18]

Glad to hear that the D-Link card got you back to the expected and desired speed.

As to additional insight I cannot really provide a specific answer as that is probably somewhere in the firmware/configuration settings between the network adapter and either the modem or the router. I scanned through the specifications for all three hoping for a "Eureka" moment but no immediate luck.

When two network devices connect they negotiate the communications protocols that will be used. A faster device will roll back to meet the speed of the slower device provided the faster device is designed to do that as is usually the case nowadays. However, that does not mean that they will agree that the fastest speed should be used even if the user configuration implies that they should do so.

My sense is that the modem and NVIDIA were able to agree (auto-negotiate) on 100Mbps. The router and NVIDIA decided (auto-negotiated) that 10 Mbps would be the speed.

Could be there is some firmware limitation/factor that prevents the later pair (route r& NVIDIA) from saying "let's use 100 Mbps via the auto-negotiation process". So they end up at 10 Mbps.....

Note:

One solution would be to force (if possible) the use of 100 Mbps directly versus Auto-Mode.

Something along the lines in this link as an example:

http://www.home-network-help.com/speed-and-duplex.html

-------

Anyway, the new gigabit card had no such auto-negotiation difficulties and happily went along with the 100 MBps agreement with both the modem and the router. "Voila" as you said....

Perhaps someone else can provide additonal explanation and insight. Always things to learn around here.