RBR750 speed cut in half with BGW320

I have searched the forum looking for a possible answer and have not found any good hits yet. I have my RBR750 directly connected to a BGW320-500 with cat6 and my download speed seems to get cut in half. I am getting 1GB to the BGW320 speed tests verify that. But even when I stand right next to the Orbi router I usually only get around 500Mbps down when I use Speedtest. There was one time I did get 800 down which was a surprise and never got that close again. I have both wifi's  turned off and I am in passthrough mode on the BGW320. My RBR750 is set to router mode. Is there something I am possibly missing or is this pretty much all I can expect with the RBS750? Thanks for any tips I may be missing.