This depends more on Upload speed than Download speed. 3.0 Mbps is your download speed, and unless you have the coolest connection ever, your Upload speed will be far less.

When set at T1 your max upload is between 31.5 KB/s and unlimited

When at T3 it's much higher (don't know how much. You can check for yourself)

If you connect as a leaf your upload max should be at least 8 KB/s less than your real max uploadspeed (the one from your speedtest) for optimum performance. You can still set your downloadspeed to unlimited.

If connected as an UltraPeer your upload speed should be more like 20 KB/s less than real upload max.

Also do the test a few times. Just doing it once can give you misleading results (here Derby was my recommended testserver, and as you can see the speed is much lower there):

12/26/2006 6:56 PM GMT 2012 kb/s 430 kb/s 110 ms London ~ 800 mi

12/26/2006 6:55 PM GMT 2011 kb/s 316 kb/s 172 ms Petah-Tikva ~ 2750 mi

12/26/2006 6:55 PM GMT 1894 kb/s 344 kb/s 103 ms Saint Petersburg ~ 1250 mi

12/26/2006 6:54 PM GMT 2011 kb/s 290 kb/s 238 ms Bratislava ~ 1350 mi

12/26/2006 6:53 PM GMT 1161 kb/s 472 kb/s 72 ms Derby ~ 700 mi

12/26/2006 6:52 PM GMT 1481 kb/s 448 kb/s 89 ms Derby ~ 700 mi

As you can see there are differences in every test. Eg. Windows or your Antivirus can decide to check for updates at the very moment that you perform the speedtest.