Gig speed - only getting 700MB down. Tips to improve?

Hi,

First time poster. Recently upgraded to Gig speed. Got new XFi gateway (renting) last week. Getting consistent speeds ~700MB down / ~40MB up. Can't seem to get higher. Did online chat yesterday and XFinity chat person said my signals are good and he sees ~1100MB download speed from my modem remotely (can they really do this?).

1) Have rebooted modem several times.

2) Have "re-activated" service. Online tech also sent modem refresh signals.

3) Speed tests are run via wired connection directly to XFi gateway - both Windows and Mac computers see similar results (all wired). Using Cat6 Ethernet cable.

4) Using XFinity speed test.

Is ~700MB the best I can expect 'real world'? - Thoughts?