Can't load large websites or download data despite speed test of 200MPS

[SFPaulyT]

I have used the Orbi system for more than a year now without problems. I have gigabit service from Comcast - have speeds of 800M with Ethernet connection, 600M at Orbi router and 125-150M throughout 3500 ft2 house. There other day the power went out and the system was down for 20 min. Since it came back up, despite still registering similar speeds on testing apps, the internet is ridiculously slow and I can't load large, data sense sites. I have rebooted and restarted the system multiple times. I also have an ASUS AC5300 that had absolutely no problem after the power outage. I am running all of the latest firmware and have tested this with multiple devices. Anyone have a similar problem?? Anyone have any suggestions?? I am ready to throw this thing in the trash. Thanks.
Paul

[FURRYe38]

What FW is currently loaded?
What is the Mfr and model# of the ISP modem the NG router is connected too?
Is the Orbi system operating in Router or AP mode?

Are you seeing problems on both wired and wireless connections with web sites? 

What is the distance between the router and satellite(s)? 30 feet is recommended in between them to begin with depending upon building materials.

What channels are you using? Auto? Try setting manual channel 1, 6 or 11 on 2.4Ghz and any unused channel on 5Ghz.
Any Wifi Neighbors near by? If so, how many?
What WPA security modes are you using?

Try disabling the following and see:
MIMO, Daisy Chain, Fast Roaming, IPv6 and Set 20/40Mhz Coexistence to 40Mhz only. Save settings and reboot the router and satellite(s).
Disney Circle: https://community.netgear.com/t5/Orbi/WARNING-Firmware-2-2-1-210-is-junk/m-p/1667485/highlight/true#...

If you updated to recent FW v.210, try enabling Daisy Chain. Some have mentioned that this seems to be working in reverse order, enabling means disabled actually.

[JoeCymru]

Shot in the dark: have you tried playing with DNS server settings? 

[SFPaulyT]

Joe
Thanks for the suggestion. That was the exact problem. I redirected the DNS to a Google server and the speed was restored. Appreciate your help. On another note, I appreciate the fact that you actually read my post and thought about it rather than spewing a prefabricated one size fits all response.

[FURRYe38]

Those are valid questions and helps us help you and have helped others. Glad it was DNS and nothing else though. Not everyone has DNS problems. 

Good Luck.