How to fix Download Speed?

Hi
i have one internet link (8Mbps) and i want share it in my local network.
when i download file from any where in direct mode (without sharing and local accounting) with 8Mbps i can download with IDM (Internet download manager) 1MBps without any
amplitude ( all the time i have 1MBps download speed)
But when i download in sharing mode (accounting) with account 1Mbps , speed i see Download speed is (onetime 128kBps , 100kBps , 130 kBps , 110 KBps , …).
in fact in sharing mode i see queues !!! it’s not good. 1Mbps can download with 1.2mbps or 0.9mbps and queues can’t fixed it and forced to stop in 1Mbps and don’t allow to amplitude download speed.
how can i fix it with queues in mikrotik?
Thanks