I have the same issue with a new vostro 3360 running the 1704 wifi card. I am considering just buying a Intel 4965 4965AGN wireless WiFi PCI-E to replace it with. I am assuming the 4965AGN will work with the dell.
I do own vostro 2560 with DW 1704 facing the same wifi problem speed falls back to 52 Mbps after veryfing all the settings.
Do let me know whats the solution.
I too face the same problem with my vostro 3560, and dell does not provide optional WLAN card during purchase even tho I requested so many times for intel 2230 or DW1901,
That worked really well for me - changed from "auto" to "aux", went from around 300 kb/s to 4.5 mb/s.
(have a brand new Inspiron 15z laptop with Windows 8, wireless card is Dell Wireless 1740)
Try the solutions listed in this forum they seem to get some bit of stabkity but nothing like other machines that I have got, Try this link too as ithe suggestions here seem to help as well: http://en.community.dell.com/support-forums/network-internet-wireless/f/3324/p/19469826/20251373.asp...
i tried to fetch the BASE OEM Driver Package - i.e. Broadcom 43142 --- below is Link to download the same - and after installing - all bandwidth and low range related issues still persist.
If you want to try those --- below is link
Just had a new batch of 3360's arrive, they have all dropped the 1704 and moved back to 1703 the 1703's work fine. My suggestion is replace the 1704's with another an intel or see if dell will swap for a 1703.