We understand you have wireless speed issues with the Intel® Centrino Wireless-N 6235.
There are some settings you may want to verify in order to optimize the 802.11n connection:
You may also update the Intel® Centrino Wireless-N 6235 adapter driver which is available here:
Please note the Intel® Centrino Wireless-N 6235 is a dual band adapter which works at 2.4 GHz and 5 GHz. However, since your router and most consumer devices work in the 2.4 GHz band and there are only three non overlapping channels some interference may be expected. In this case we recommend moving your system away from devices working in the same frequency or attempt to use other non overlapping channels as described below:
You may additionally test the connection with a different router model.
I hope the suggestions help.
I just bought a new router which I intend to install tonight. I am hoping that this will help performance consistently. Adapters on my older laptops consistently perform well with WRT54G router while this one doesn't and in fact I did not find a setting that will get performance level of Intel® Centrino Wireless-N 6235 same as the others. The difference is is between 15x to 2x slower. This is why I asked if there are any known issues with WRT54G. Once I install the other router (Apple Time Capsule router/storage) I will report the result here.
SInce I promissed to report if changing the router helped the performance here it is: the new router did not help my DELL XPS perform better on wireless network. After this experiment I spent quite a bit of time with DELL support. They finally found in their notes that Intel Centrino Advanced N 6235 does not perform well with the topology of the DELL XPS motherboard. DELL recommended replacing wifi adapter with one that was specifically designed for that hardware. I wil everyone here know if that replacement helped. If that proves to be true the conclusion will be that anyone purchasing DELL XPS or some of their other laptops should not be chosing Intel Centrino Advanced N 6235 as wifi adapter.
I hope the computer manufacturer will resolve the issue for you based on their explanation.