[NAME] , yes you can upgrade your wireless to a better one.  Verify that you have a PCIe mini card.  Follow the instruction on page 21 and be careful with those tiny antenna.  
Hi, I have a Dell Inspiron 3847 desktop.  I recently had the internet connection to my house upgraded to 400MB download speed but I am only getting about 40MB download on my desktop (other devices are getting the full speed).  I assume that is because the wireless card (Dell Wireless 1705 802.11b/g/n (2.4GHZ)) in my computer is outdated.   Can I upgrade the card in my desktop or since the computer is relatively old, are there other limiting factors in the computer that will prevent me from getting close to full download speed?  If an upgrade will help, what card should get?  Thanks.  
Upgrade Wireless Card in Inspiron 3847