One computer out of four on network VERY slow

Giganews Newsgroups
Subject: One computer out of four on network VERY slow
Posted by:  BillyBob
Date: Tue, 27 Dec 2005

Here is a crazy one for you.  I have recently set up a wireless network
adding a D-Link 524.  The desktop is hardwired by ethernet, and I have a new
Acer computer with a Broadcom network card.  The network is WPA encrypted.
After the usual difficulties of getting these things up and going, I now have
download speeds on my laptop that are virtually identical to those on my
hardwired desktop.  So my daughter and son-in-law arrived for a Christmas
visit, each carrying their own wireless laptops.  One was a brand new IBM
with an Intel network card, the other a much older and cheaper IBM laptop to
which was added a Linksys card.  After I gave them the encryption code, the
older laptop connected immediately and worked pretty darn good for the
several days of their visit.  From the word go with the newer laptop,
connection was a hassle.  Or I should say, pulling up web pages was a hassle.
It would connect almost every time.  It would show a strong signal almost
every time.  Sometimes it would indicate 54mbps throughput, but that would
constantly oscillate down to about 1 Mbps.  But regardless of signal strength
or throughput indicated, it was almost impossible to use the Web.  When I
check download speed at PC pitstop, my speed (with either my wireless Acer
laptop or my desktop) will usually be between 2700 and 3000 Mbps, from a
provider who is advertising 3500.  When we would try this on the newer IBM
laptop, even when the signal was indicated as very strong with high
throughput, we would get between 61 and 600 Mbps!  Sometimes when he first
connected, web pages would come right up, but within a few minutes it would
bog down to unusable.  In the meantime, his older beat up IBM laptop with the
added Linksys card functioned just fine.  Then we took his laptop and went
out around town, where it easily and consistently connected to any number of
WiFi hotspots, and some other private unsecured networks, which we hooked up
to for a couple of minutes for test purposes.  Come back to the house, show a
very strong signal with up to 54 Mbps yet can not connect to anything!  We
experimented with MTU, lowering them from 1492 down to 1468 after having done
the appropriate ping testing.  We set all computers in my network plus their
two laptops to this lower MTU figure.  Lowering the MTU and increasing the
RWIN definitely improved in the download speeds of my two computers in the
network.  But doing the same on his laptop accomplish nothing.

Any ideas, anyone?  I did not bother getting rid of encryption, since he had
no problems connecting to my network.  It's just that once he connected, he
might be able to go to one or two web sites with a reasonable speed, but
every time within five minutes his download speed would drop to almost
nothing.  We are quite mystified.  But his laptop works wonderful at his home
as well as on the road and hotels, airports and various WiFi hotspots.  It
only refuses to function correctly on my wireless network.