I think my speed may drop soon and again why are my actual speeds faster than my line speeds?
By actual speeds, do you mean throughput?
Sync speed = line rate = Bearer (or Path).
Max rate (from a HG612) = Attainable rate.
From my HG612:-
Max: Upstream rate = 4946 Kbps, Downstream rate = 22496 Kbps
Bearer: 0, Upstream rate = 4928 Kbps, Downstream rate = 20488 Kbps
My Max (attainable) rates are higher than my Bearer (sync speeds).
Also:-
Down Up
SNR (dB): 5.6 6.2
Occasionally, when a connection syncs at very close to attainable rates (when SNRM is around the target 6dB), attainable rates can end up lower than sync speeds when SNRM lowers, usually in the evenings.
It may be worth rechecking between noon & 14:00, when SNRM is usually at its highest level.