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saoirse1916Flag for United States of America

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WiFi LAN speeds at 10% until disable/enable

I've got a new laptop with an Intel 5100 AGN card connected to a D-Link DIR-655 router.  When my PC is connected via ethernet I can transfer a large file (2+GB) at around 12MB/s (96Mb/s) which is great but over WiFi I'm getting about 500KB/s (4MB/s).  If I disable and then re-enable the WiFi adapter, it transfers at around 6MB/s (48Mb/s) which is still way off of the 150Mb/s I'm allegedly connected at, but it's good enough for me.  I've tried updating the firmware for the 5100 though it says it's already current, and I have already updated the router to the most current version, so I'm at a loss as to why disabling and re-enabling the card would make such a difference.

Thanks to anyone who can point me in the right direction!
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Rick_O_Shay
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Is the wireless mode of the adapter maybe getting it to connect at a,b,g before going to N or something like that.
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It says it's connecting at 150Mb/s which I believe is N, so I don't think that's it.  Is there any way to verify that though?
I am not seeing any way on XP. Maybe look from the AP/router at connections there?
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There are so many factors that can affect wifi speed and keep in mind that you can get only about 50% of usefull througput on declared bandwidth.
At this post you can get samo good advices:
http://www.smallnetbuilder.com/content/view/30664/228/

Look at graph at the end - on the 150Mbps (300Mbps withr dual band) router, the maximum achived speed was 48Mbps (59Mbps).
Maybe you can try to use InSSIDer to scan your area and choose the channel with less interference.
http://www.metageek.net/products/inssider

I am more worried about 10% speed before reenabling card. I would try to update drivers and also try some other wlan card. The cause could be incompatibility between router nad wlan card.
The Xirrus wifi tool does show what band is in use if you want to see if that is what is happening.

http://www.xirrus.com/library/wifitools.php
I do have another WiFi card, it's USB and B/G only but it might be a good test.  It's the disable/re-enable that causes me concern to.  I get good speed for a while (the 10 minutes or so it takes to copy a 3-4GB file) and then the next time I need to copy a large file, I notice that I'm only getting the 500KB transfer rates.  I thought that it might have something to do with power management, i.e. the system shutting down or downgrading the card, but I double-checked that and it's set to maximum for both AC power and battery.

BTW, this is a Windows 7 x64 system, if it matters.  I'll try the other card tonight if I can find it and post back with my results.
Also, I read that smallnetbuilder article and they mentioned something interesting: separating B/G devices from N devices.  I do have an old G router that I might add in and connect everything else to, since my laptop is the only N device that I own at the moment.
As stated, try updating the drivers - OR, DOWNGRADING the drivers if a previous version is available.  Years ago, I read an article that described just how significantly drivers can affect performance.
Interesting...I added an extra G router to handle the G clients that I have and now my machine is the only thing on the N router.  I'm now getting transfer rates of around 3-4 MB/s...a bit slower than I was before.  Also I'm running inSSIDer and it's identifying both networks but clocks the N router at 11Mb/s and the G router at 24Mb/s on the speed indicator.  Somehow it's as if the N router is running in B only mode (it's not, I've triple-checked.)
Also, I'm not finding anything in the 5ghz band...not sure if I should though.
the 5Ghz is for 802.11a clients.
Separating a/b/g and /n clients is always good, you could however create severeal SSIDs on DIR-655 (at least I think i remember this)

THis might also be down to power saving, which is supposed to be quite good (i.e. tends to be over-active on WiFi at times. Try looking at Power Scheme in Control Panel. Go to advanced and make sure the Wireless Card has Maximum Performance always ...

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davorin
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Unfortunately I already checked power saving and the card is set to maximum on both battery and AC power.  I disabled the other router and all devices connected to it so it's just my N router and my PC.  Now I'm transferring reliably at between 9-10MB/s, so a big improvement!  With the other router on, I would get 1-2MB/s max and about 10KB/s min...so there's clearly some interference going on somewhere, and it may be the router.  It's actually an N router that I took out of service because it dropped the signal too often...might just be a bad one.

It seems like my next step is to get a decent G router and start bringing devices back online and see which one hurts my connection (if any).  Thanks for the help!

By the way, yes, those are the only two WiFi networks that I pick up...I live in the boonies.
jakob_di: I looked into the possibility of running multiple SSIDs through the DIR-655 but unfortunately that's not an option with that model.