Net speed problem on one Vista desktop


I have been facing a strange net speed problem, on a site with 2 desktops and 1 laptop all with Vista SP2 and fully updated, and all technically about the same generation ab. 2 max. 3 years old.

The other desktop and the laptop behave all well on a nominal 24/1Mbps ADSL-line via an older ADSL2+ modem/router through both WLAN and LAN connection, reaching acceptable speeds of some 6-15Mbps on dl and 600-800kbps on ul, but the other desktop is crawling on some 400-700kbps on dl and about the same level or even higher on ul.  The pings for all are on the same level of ab. 30ms on close test sites and up to 300-400ms on faraway sites.

What could be the reason for this behaviour on the crawling desktop, as a machine besides on WLAN and on same LAN line is working well?

I have been checking e.g.
-  no malware or viruses detected on this problem machine by 3 different scanners, just some few cookies
-  all cable connectors and antennas on the machines and router are checked tight
-  machine antennas are on open space less than 10 metres apart the router antenna
-  the net component drivers are updated and also once deleted/renewed on this problem machine
-  the ipconfig /flushdns is done
-  the disk check with /r is done
-  the behaviour is the same with or without Firewall on
-  the behaviour is the same with IE8 and FF3
-  but, for some reason, I didn't get LSPFix check working on Vista

Please, give me a hint, if there is still something I may have been missing to check.

Thanks in advance.

Best regards,

Pete V.
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bitlaConnect With a Mentor Commented:
What are the actual dl/ul speed from your ISP?
Have you turned off the other desktop and laptop and checked the speed?
Have you verified the network speed in task manager --> networking
Is it 100Mpbs or 10Mbps or less than that.
IN XP there is an option to use Full duplex or Half Duplex settings for the network adapter(properties) ,Check whether its in Full duplex  ( i am not sure if the option is there in Vista )

And last thing is windows reserves some bandwidth (20%) default, it should not be more than that.

To the check reserved bandwidth

Start->Run->type gpedit.msc
Expand the "Local Computer Policy" branch.
Expand the "Administrative Templates" branch.
Expand the "Network Branch".
Highlight the "QoS Packet Scheduler" in left window.
In right window double-click the "Limit Reservable Bandwidth" setting.

If u change the settings type in gpupdate and press enter
Maybe Remote Differential Compression is the cause?:
Try this:
Start/Control Panel/Programs and Features
Click on ‘Turn windows features on or off’ on the left side of the screen
Uncheck ‘Remote Differential Compression’
PeteVfiAuthor Commented:

Thanks for the replies.

But, sorry, no solution so far.

The dl/ul speeds are the same level anywhere.
Tested also as online alone.
On Task Manager Networking speeds for WLAN are 54-11Mbps and network usage 0.5-7.5%
On LAN adapter Auto Negotiation and Full Duplex100Mbps tested, on WLAN it's automatic and there are no settings for this
The OS's are Vista Home Premium and do not have gpedit.msc, but I copied one from a Business machine and it opened, but got into error, couldn't load contents.

Checked the RDC disabling, but no dice, and, the well-speeded laptop do have it enabled, sorry.

Still desperately chasing for solution.

Best regards,

Pete V.
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John GriffithConsultantCommented:
See if speed is also slow in SAFEMODE w/ Networking.

If speed OK, then start-up app likely candidate.
bitlaConnect With a Mentor Commented:
clarify whether it is 54 mpbs or 11mbps, it should be 54mbps , if it is 11 mpbs then your signal strength is low hence to maintain the connection the wirless card is reducing the speed to 11mbps.

So the calculation 11Mbps at max of 7.5% == 11x7.5/100=0.825Mbps=825Kbps
and with 54Mbps at 1% =540kbps
and at 0.5% = 270Kbps

hence you are getting low speed due to signal strength.

I suggest you check the Acess point channel and it should be same on you network adapter.

I recommend you to install Network Stumbler to check the signal strength and channel.

PeteVfiAuthor Commented:

Thanks bitla for your reply.

Yes, the WLAN speed is varying automatically time to time between 54 to 11Mbps at certain different levels, and the signal strength is ab. 3 of 5 visualized steps.

But, this do not clarify, why the 10/100Mbps LAN behave exactly on the same low speed levels as the WLAN ...

I'll check now some things by remote control, but will go to the site anyway later today and tomorrow, and will come back with some status notes.

Best regards,

Pete V.
bitlaConnect With a Mentor Commented:
install Network Stumbler on the desktop and checkthe signal strength and channel number of the access point.
PeteVfiAuthor Commented:

OK, yess, the WLAN problem point found!

It was the small 8.7cms/3.4inches antenna on the WLAN card located behind and down the machine box under the office table against the window wall and radiator, too "faraway" getting/giving too weak signal.

When replacing it with a small 8.2x8.2cms/3.2x3.2inches mirror antenna with a pigtail cord, placed on the machine box top and directed optimally, the signal got to 5 of 5 visualised steps and the transmission speed steady to ab. 54-48Mbps giving some 14.0/0.8Mbps speed for this nominal 24/1Mbps ADSL-line, great!

But, the obviously about same level speed problem on the LAN connection to the same ADSL-modem/router is still remaining ... I may chase for a solution for it later on, still checking all the cablings and some other details between and within the machine and the router.

So, now I thank bitla for most accurate advices for this troubleshooting, giving all the points to him dividing them to all his 4 replies!

Best regards,

Pete V.

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