Your mixing up to terms MB/s and Mb/s they are diffrerent by a factor of 8. 1.5 MB/s is shown as the speed ur downloading , that is equal to 12Mb/s which is 12% of your 100Mb/s connection to your rotuer (NOT to your ISP), which is then connected to your ISP There will then always be other bits of trafic flowing which will effect the speed a bit, but there is nothing strange happening here so technically i can only transfer around 15MB/s across my network? is that the truth?