ADSL Speed Decrease

For a year or so my ADSL internet (Zoomtown) was doing about 1500 kbs down and 750 up...

Now, within like the past week... it went down to 800 down and 650 up.

I know for sure that Zoomtown didn't decrease their speed or anything.
I plugged directly into my router to ensure best testing. I tested via zoomtowns own speed test (on thier servers) and about 4 other speed tests... got pretty much the same results. When I download stuff, from anywhere really, it's pretty much capped at 100kb/s... it used to do 200 or 225.

So what are some possibilities or reasons that the speed would pretty much just half itself instantly? I know it's not my computer either, I've tried 3 computers on my internet, all with the same results.

 

Problem fixed.

My router was plugged into a desk unit that is basically a powerstrip with a phone cord too... so a standard phone cord was going from the wall to the desk unit, and then the cord that come with the router was going from the router to the desk unit. For a while it was working perfectly fine like that, I was getting 1.5 mb/s... and all of a sudden it dropped to 750 kb/s.

So I plugged my router directly into the wall and now its a good 1.8 mb/s.

Sweet.