I have a prepaid T-mobile Broadband data plan with Huawei UMG366 4G modem (TMO Jet 2.0). The best signal reception I can get in my house is -93dBm. Download speed tested at www.speedtest.net varies from 1.5Mbps to 6 Mbps, occasionally gets as high as 8Mbps.

The problem is as follows. When I initiate data transmission, for example, hit <BEGIN TEST> button, the actual data transmission begins after a delay, which varies from 0sec to a few seconds.
And even after a huge delay of 5s, the download speed can be at maximum (6+Mbps). So the download speed is not directly related to the delay time.

I have never seen such delays with other Internet connections.

What could cause such a delay? Could it be due to relatively weak signal? Can I tweak anything on my side? Can it be related to NDIS VS PPP connection mode?