AC1750 (Archer A7) slow wired speed
I bought two TP-Link AC1750 routers, one to use for my parents' house and one for my house. I set mine up, like the admin, works right away, good range, etc. I updated the firmware. However when I try a speed test (speedof.me) from my wired computer, I get 15-20 Mbps or so download speed. It actually doesn't even peak much higher than that, like 30 something. I did a speed test at Charter's Ookla page and also got around 30 Mbps there. Prior to the router change I used a Netgear N750 WNDR4000 and got right around 100 Mbps.
I have done a bunch of speed tests since then, and only one time it did peak higher than the 30s - it peaked right at 100 actually. So that's interesting, it can go faster. I have some screenshots of speed tests if needed. I have power cycled both modem and router in there as well. It seems normal and quick enough for web browsing, but I did do a big Steam game download that was slow.
Yesterday, I made it to my parents' house and swapped their router for the second AC1750 I bought. It works right away as well, and I did not update the firmware. It gets about 125 Mbps in speed tests when before it had gotten 100 Mbps. Great, a little improvement. It's probably modem-limited since that hasn't been changed in a long time (and same for mine). So I'm fine with that. We both have Charter Spectrum service, and we can try swapping in newer modems later.
So riddle me this, what's going on with my slow router? What can I check? The updated firmware is one obvious difference, but I'm doubtful on that. I wish I had done a speed test before updating firmware on mine. Mine was a v5.8 and my parents' was a v5.0 so that's another difference. I set the wifi network(s) name and password on both. I have a NAS at my house and I reserved the IP it had so that wouldn't change. I also set port 80 forwarding for it initially, but then I noticed it was in the UPNP already so I removed my change. I have not yet tried powering down my NAS to see if it is going nuts and using all my bandwidth for some reason, but it didn't prior to the change. I think I will try different ports next. I'm stumped. I saw someone with a similar problem in an old post here was asked about NAT boost being enabled, but I didn't see that in the menus.
Thank you for any help!