You can optimize the performance of downloads by configuring BITS through Group Policy.
You can use to use Group Policy to configure network bandwidth that BITS uses.
Note : If you are going to change BITS bandwidth settings don't forget these settings are system wide, they are not application specific, so every application uses BITS will be affected. the BITS settings will affect BITS in any application.
To configure BITS bandwidth settings.
1.Run Group Policy Object Editor (Start>Run>gpedit.msc).
2.Browse Computer Configuration>Administrative Templates>Network>Background Intelligent Transfer Service.
3.Open the "Maximum network bandwidth that BITS uses (BITS 2.0)" or "Maximum network bandwidth for BITS background transfers (BITS 3.0)" setting.
4.Set the transfer rate in kbps that you want BITS to use (the default is 10).
5.Set the times at which you want to limit the bandwidth (the default is 8:00 A.M. to 5:00 P.M.).
6.Set the limitations to be used outside of the designated time (the default is Use all available unused bandwidth, but you may select another limitation).
7.Click OK.