Gigablast only going 500-600 Mbps

Hello all,

I recently upgraded to Gigablast service and it's only going 500-600 Mbps.  I'm using a Netgear CM1000 modem and an ASUS RT-N66U on a wired connection.  Is there a COX rep that can check my connection and push any firmware updates for my CM1000 that you have?

Also does anyone have any suggestions on anything else I can try?  My upload speed does reach the max advertised about 35Mbps.  Any help would be greatly appreciated.  Thanks,