I'd first like to say I am not a networking guru by any means but would like a question answered by someone who may be.
I've been playing around with my TCP/IPv4 Primary and Alternate DNS addresses to see if I could increase my download speed. I'm not really worried about the upload speed since I don't upload much. My ISP is Comcast and my contract speed is 100 Mbps. I used two (2) tools, DNS Bench and DNS Jumper, to see which DNS addresses showed the best performance for my area. I'm not sure why but I got different results between the two tools. I also used speedtest.net and SpeakEasy to measure the performance as I changed the DNS addresses. I used typical DNS server addresses from Google (18.104.22.168, 22.214.171.124), and the top performing addresses from the DNS tools along with several others including ones from my ISP. Typically I averaged around 80 Mbps. Also as a side note, I use a NetGear Nighthawk X6 (R8000) router. As I tested, I would change the DNS addresses on both my PC and router. I don't think it's necessary to change it on the PC since the router is the last device in the line before going out and basically the PC DNS addresses are ignored. I could be wrong here so please correct me if I am.
With that background info, I decided to see what would happen if I used my default gateway ip address as my primary DNS. So let's say my default gateway address is 192.168.1.1. I then set my primary DNS Server address the same as my default gateway address (192.168.1.1). When I ran a speed test on the sites previously mentioned, to my surprise the download speed increased to above my ISP contract speed. I ran the tests several times averaging 114 Mbps.
Now for my question. Do you see any issues with doing this? Any risks, etc..? If there is any info I left out that may be helpful in answerng my question, please let me know and I'll provide it. Thanks in advance!!