Mac Mini Internet connection problems!

I have a fairly simple problem with my mac mini desktop.

First off, These are the specs: Mac mini "Core i5" 2.5 (Mid-2011) Specs (Mid-2011, MC816LL/A, Macmini5,2, A1347, 2442) @ EveryMac.com

Second, My problem is with the Internet connection on my desktop. Im a first time poster in this forum so I might be posting in the wrong location.

I recently purchased this model of mac mini and it was running smoothly until I tried downloading World of Warcraft onto it and running other downloads such as adobe flash and microsoft silverlight (To get at least youtube running).

The problem was that the download speed was running at 4.6kbps. And my last computer was clocked at 10mbps. Now I know standard bandwidth isn't measured by clocking, more by usage, but as we all know, With that kind of clocking you'd get at least 1-2mbps download average. I had the wifi and the 'Ethernet cable' connected at the same time. The only ethernet port it has. And upon disconnecting the wifi, The download speed did not vary in change at all.
But upon disconnecting the Ethernet cable I've been getting at least 1.5mbps speed on downloading.

Could there be a fault on my ethernet port? Or is there a problem with both connections conflicting with each other? Because if so Im wondering why the wifi of all connections is running faster than the direct ethernet cable itself.

The router and modem are working at perfect capacity for me considering my last computer was plugged into it fine. Its this computer in particular I'm having these troubles with.

Thank you.

On my iMac and Mini even if the WiFi is turned on and connected, the Wired port always takes over if plugged in and I get my full 6MB internet speed through it.

That sure does not sound right but right now I am at a loss to what is the issue.

What is your Modem and Router? Make and Model? Who is your ISP? What speed tests are you running?

Seems that less cords connected = greater speed. now if I need to print something I plug ether cable into router, print, unplug. It would be nice if someone would print a SIMPLE PICTURE description of how and why things are connected the way they should be for optimal performance. This seems to be the equivalent of the "12:00" blinking on VCR's.

To figure out my predicament I simply unplugged ALL the DSL & phone cords. 1) Plugged phone (DSL) line into modem. 2) Plugged DSL cord into a multi-DSL router. Turned on Wi-Fi on computers and iPad. Did speed test on all 'puters and found out that I get close to my 12 Mbps (10-11). When I introduce Ethernet to hardwire the computers and peripherals, it (being the machines) decide which ports to use, and therein lies the problem... LIKE I SAID... Something graphically simple with colors and simple to follow directions that show you what happens when you do something would be greatly appreciated.