MikroTik RB951Ui-2hnd --- 3g issue

Very Slow browsing and connectivity.
I do have a 3G dongle connected to RB951Ui-2hnd.

do we have to trigger the speed and bandwidth in script.

Is there any default speed and bandwidth for 3g.

However the same router connected to wired has good browsing.

Nothing to do with signal strength as the same datacard has good speed when connected to a laptop.

The speed depends on the ISP.
A good connection is necessary.