Enabling wifi adapter causes slow laptop until reboot OR while AC adapter is plugged out

Question

It's been a couple of weeks now that I feel that my pc is feeling slower than usual. Not just network related things but just about everything gets a delay (timings at the end of the post). It's like my IO decides to take a nap until the next reboot.

I couldn't really pinpoint what was causing the issue until I restarted my laptop with the hardware switch to turn off the wifi off in it's off state. Suddenly the machine is working at it's full speed again! Sure though once I turned wifi back on everything slowed down again. Even enabling wifi adapter without connecting to any network slows everything down.

A person would think that switching the adapter back to off disabling the adapter would fix the problem again but no luck there. The only fix to have the system run fast again is to reboot the system with the hardware switch off.

Even when I work offline without any connection whatsoever the pc stays slower...

One other thing I noticed is that when my AC adapter isn't plugged in the pc seems to go faster again (on balanced and high performance power setting) which completely makes no sense :/

My laptop is mainly connected using gigabit connection to the company network but I also make a wireless connection to reroute all the internet traffic through the wireless network.

Things I already checked/changed/tested:

• renew all adapters (either using ipconfig or by pulling out cable)
• Disabled bluetooth adapter during all the tests
• Updated the network adapter drivers to their latest version
• The routing table is identical before enabling / after re-disabling the wifi adapter

My system consists out (relevant items):

• Dell Latitude E6520 Running Windows 7 64 bit
• Wireless network card: Intel centrino advanced-n 6235 (driver v: 15.9.0.5)
• Wired network card: Intel(R) 82579LM Gigabit Network Connection (driver v: 12.6.45.0)

So if anyone can point me in the direction on what this could be caused by that would be a big help!

---

Testing results (all averaged from 3 trials):

Starting current developing app from visual studio  
Before Wifi on:   4.4 sec  
After Wifi on:   14.7 sec 

Starting Windows Explorer
Before Wifi on:   0.4 sec  
After Wifi on:    1.3 sec 

Going to lockscreen
Before Wifi on:   0.4 sec  
After Wifi on:    1.5 sec 

Network connectivity before Wifi on: After wifi was turned on:

Solution

Okay, ultimately when I did some more tests with AC adapter in and out it felt strange that the laptop ran faster again with the AC adapter out.

When I tested with another Dell adapter the laptop ran it's normal speed again. How the wifi hardware switch is connected in this story, I don't know, probably some electronics story there.

The old AC adapter: LA65NS0-00 19.5 V - 3.34 A
The new AC adapter: FA90PM111 19.5 V - 4.62 A

So if you also have the issue that your pc is running slow mysteriously and you have a Dell PC, check your adapter first, maybe it isn't powerful enough or the detection pin is broken (Dell AC adapter has a logic/signature pin, you can see it in the middle of the plug). My story is that I received a wrong adapter from the IT department.

Comments

[Ramhound]

How can you be connected if WiFi was disabled??

[Sarah-Ann]

Forgot to mention, I connect using ethernet gigabit and wifi, updated my question.

[Ramhound]

Your wire connection would not result in a wireless connection to those devices. How many WiFi adpators do you have installed? A wired connection would NOT have a signal stregth. It sounds like you have hardware that is causing the problem, using an external adaptor, might solve your problem. I have seen nothing but problems with the Intel Centrino adapator in every device I have worked with one.

[Sarah-Ann]

Those devices are other devices in the wired network and the test I am running is a tool form the Incredibuild build helper to test the connection speed to other build helpers in the network, it has nothing to do with the wireless connection ;)

[Sarah-Ann]

Anyway, problem solved, see my answer.

[Ramhound]

Took me awhile to realize what the tool was doing. It is able to determine the signal strength by communicating with the access point ( gotcha ).

[Ramhound]

Its pretty clear. Your laptop requires more then 3.34A to work. When your AC adapter is plugged in your battery is disconnect or placed into a mode so it can be charged. This means all power requirements must come from the adapater itself. My guess you confused the adapters you were using with a different laptop.

[DarkDiamond]

This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review

[joshfromtexas]

My answer is unplug the Wi-Fi card and use the USB Wi-Fi dongle to get back to the normal operation.