Question Router speed drop while using 2 routers

[busu3]

I live in a house with two floors. Initially I had only one router which is a TP-Link archer C6. I getting consistent speeds of 250 Mbps on all my devices. The problem was that the range wasn't enough for the top floor. So I decided to use a second router for the top floor connected to the first router. I set the second router with DHCP off and connected it to one of the ethernet ports on my first router. The second router gives a speed of 100Mbps without any drops or any issues. The second router however, gives a speed of 250Mbps initially then the speed drops in steps down to 1 Mbps or so then it increases for a bit to 10Mbps. The upload test does not run at all. This happened first in my phone but I thought it was the phone's problem but my laptop is also facing the same issue now. What could be wrong with the first router? The second router is a netgear R6220.

 

[Lutfij]

Don't you think adding a repeater or a range extender in order to add more range would've been a good idea? If you're the owner of the house you speak of, having a higher tier router and placing it smack dab in the middle of your household(if you imagine your crib to a hamster ball) then you'd be able to get coverage to practically all corners of your crib.

At this point, I'd try and see how far just each router, standalone, gets you when you have it mounted up on a wall, with the device in the middle of the house(in the literal sense), make sure you're on the latest firmware for both routers and perhaps replace the TP-Link router with the Netgear but you won't get much IMHO.

Got a way to share a floor plan and elevation/section of your crib? I'm an architect, hence why those terms might seems out of the blue.

 

[busu3]

Don't you think adding a repeater or a range extender in order to add more range would've been a good idea? If you're the owner of the house you speak of, having a higher tier router and placing it smack dab in the middle of your household(if you imagine your crib to a hamster ball) then you'd be able to get coverage to practically all corners of your crib.

At this point, I'd try and see how far just each router, standalone, gets you when you have it mounted up on a wall, with the device in the middle of the house(in the literal sense), make sure you're on the latest firmware for both routers and perhaps replace the TP-Link router with the Netgear but you won't get much IMHO.

Got a way to share a floor plan and elevation/section of your crib? I'm an architect, hence why those terms might seems out of the blue.

The thing is I had this netgear router initially and it wasn't working properly. So I bought this archer c6 but as I said coverage was not enough, so I decided to use the netgear router to extend the range. I tried moving the first router but the range was still not enough. I don't have the floor plan with me right now. The problem is the slow speed on the primary router.