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Different computers - different download speeds

PortyAL
Dabbler
Posts: 23
Registered: 30-08-2007

Different computers - different download speeds

Hi

I've 2 laptops on my wireless (b) home network. One is a Dell Inspiron 510m and the other is a Dell Inspiron 2200. Both have the same spec (1300Mhz, 40Gb HDD, 512mb RAM)and have the same firewall (Zonealarm).

Speed tests on www.mybroadbandspeeed.co.uk, have showed that my download speed on the 2200 almost double than that on the 510m. A test today gave a speed of 2.8mbps on the 2200 and 1.5mbps on the 510m. The 2 PC's were sitting side by side at the time.

Any theories as to why there would be a difference would be greatly appreciated.

Thanks

AL
7 REPLIES
Walrus
Grafter
Posts: 394
Registered: 30-07-2007

Different computers - different download speeds

Assuming both are connected to the same wireless router, and signal strength being better than abysmal, there is little that would throttle the bandwidth that dramatically. Is it consistantly repeatable? Is the 510m ever faster than the 2200?

The only thing that springs to mind is USB.... 1.5Mbps is the speed limit of some old USB 1.1 interfaces. Is your 510m connected wirelessly via some USB interface?
The_10th
Grafter
Posts: 1,090
Registered: 08-04-2007

Different computers - different download speeds

What network card configuration is used - e.g. half duplex and full duplex found under adapter settings for the NIC?

Also, did you lock internet useage using Zonealarm on the PC not running the test to ensure no background processes are running that you weren't aware of?

<shouldn't this be in the 'hardware forum?>
Community Veteran
Posts: 26,339
Thanks: 595
Fixes: 8
Registered: 10-04-2007

Different computers - different download speeds

Have you checked if the MTU is the same on both?
jelv (a.k.a Spoon Whittler)
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Ianwild
Grafter
Posts: 3,835
Registered: 05-04-2007

Different computers - different download speeds

MTU and RWIN differences would be my guess - It can make a huge difference.

Start at http://www.kitz.co.uk/adsl/MTU2.htm for details on stuff you could try.

Ian
rikmoncur
Grafter
Posts: 136
Registered: 04-08-2007

Different computers - different download speeds

good grief!! I've just downloaded drtcp and my speed has jumped.
I've never got more than 2.5, now it's more than double - one speed test hit 6.8!
Community Veteran
Posts: 3,364
Thanks: 15
Registered: 06-04-2007

Re: Different computers - different download speeds

Quote

Any theories as to why there would be a difference would be greatly appreciated.


Weird things happen if one laptop connects on 802.11b and the other connects on 802.11g, I think you put a (b) in your message to indicate you have a fixed 802.11b network. Is this correct? Are you really sure this is true?

Also, does the 510m, the device with the lower download speed have the wifi that has a 'low power mode'?

SW.
edit: corrected typo
--
3Mb FTTC
https://portal.plus.net/my.html?action=data_transfer_speed
Community Veteran
Posts: 1,931
Thanks: 4
Fixes: 1
Registered: 01-08-2007

Different computers - different download speeds

I would agree with Ian here, and hazard a guess at RWIN. I had a desktop running at 5Mbps, but my laptop connected via a PC card wireless adapter could not get better than max of 2.5mbps. I ran a test and adjusted the RWIN on the laptop, and now everything is OK. Try this site, www.dslreports.com and run the tweak test under tools, and see if it recommends adjusting your RWIN and MTU. It may just solve the issue.