Ok, I bought my laptop in Jan 2013.
It is a gem, works great in every aspect (although touchpad and screen aren't top notch).
Except as we all know WiFi ***. I've been following the mega thread on 6235 N card which has been closed and I've been searching every forum on internet for past 2 years to fix this just to come to a dead end.
AFTER THE BELOW OBSERVATIONS:
Everyone think its the Intel Centrino Advanced - N 6235 adapters problem BUT thats not the issue
as I managed to switch the card to a different laptop and it performed flawlessly (5 Bars of wifi signal , tested over 2 days).
On my L421X ultrabook the signal fluctuates from 1 bar to 5 bars and the internet is practically not usable while anything under 4 bars which is a big load of 3 yr old ***.The only thing that got fixed with Intel 17.x series drivers was complete dropout of wifi.
CONCLUSION IS:
The L421X was manufactured without testing its wifi antenna capabilities properly.
I am frustrated because I can't even call DELL as I am out of warranty and DELL sold me a $1000 Ultrabook in 2013 with WIFI design FLAW.
During the past 2 years I've suffered so much because of this laptop , bought multiple routers, had to use wired connection to get my internet working (whats the point of buying a $1000 ultrabook).
BTW incase you reply to this, dear DELL customer support please continue to read below:
1. Wi-Fi adapter power settings : Maximum Performance on plugged and battery
2. Drivers : Latest 17.x of Intel Drivers and Dell Support downloads drivers (tested both over a week or more)
3. I don't have a microwave near my laptop or router, in fact I threw mine out of the house.
4. No 2.4Ghz wireless Phones in my house
5. Switched All channels on my routers (1,6,11) and tested over long periods of time
6. It is definitely NOT interference
7. Router Transmit power = Maximum (router is not the issue as I bought multiple routers and they all work perfectly with my Latitude E6430 5 Bars all the time)
8. Adapter's Advanced config also tested on default as well as tweaked settings (No improvement)
Finally I just wanted to say, I don't want your apology with words like "sorry to hear your bad experience with our product" . I've seen plenty of that with hundreds of L421X customers. After taking the time and pain to create an account here just to post this, let me tell you that I am not buying anything from DELL again since you guys literally failed to fix this over a course of 2 years. I hope this teaches DELL a good lesson as they are loosing a customer who would never again buy from them.
Once again, good work DELL keep it up, you failed yet again. No wonder Alienware became a piece of ***.