Router / Internet problems

[poser..]

Okay so to start off, I've only had like 1 internet "issue" in the year that i've moved to my new house. Now, I'm starting to have some issues that nobody can seem to figure out. First, I notice my ping in games is much higher than it normally is, like 10-20ms higher. Next, is my download speed. I pay for 400mbps down. Not getting that of course, its pretty much anywhere from 70-90 every single speed test. I had to go to work the first day the problems started so my mom decided to call my isp, but maybe wasn't able to articulate the problem very well, she said that they wanted to send us a new modem, since speeds were the same when bypassing the router. This wasn't the problem because speeds used to be normal. Today, we had a technician come to our house and he could not find any problems. The only thing that i can think of is if maybe i have a router firmware update? I'm lost at this point as everything i have tried doesn't work. I've tried restarting router, resetting to defaults, restarting from my isp's end, the speedtests are lower over wifi and ethernet, doesn't seem to matter.

If you guys have any ideas that would mean a lot. Thanks :D