I've noticed that Windows Updates, OS X App Store downloads, Xcode betas, etc, always seem to come down at ~30Mbps.  Sometimes they go fast (~7-8Mbytes/s) for the first 30 seconds or less, then they drop back down.  I have monitored bandwidth using the OSs tools, and the bandwidth monitor screen on my router.

I can pull things down faster with several TCP streams, but shouldn't need to for downloads within NZ.

My laptop is plugged into a gigabit switch which is plugged into the router, a Mikrotik with fast-track turned on.  The gigabit switch and the ONT are both plugged into gigabit port

Is this just me, or a wider problem?

(Edit: I'm in Whanganui, 100/50 ("Pure"), UltraFastFibre is the LFC, my router is an RB2011UiAS-2HnD).