Why bad internet on Macbook Air?

Question

macOS

Good day to all.
I have a D-Link DIR-615T at home. He does not ask to eat, everything is fine.
Wi-Fi set up as standard (no quirks)

Here is the settings screen

But recently, I bought a bushy and old Macbook Air "11 Mid-2011. I rolled up MacOS and it's time to connect to Wi-Fi. I connected, but the pages do not open, I started watching ping up to 8.8.8.8 and there are cosmic numbers. Delays of 5 seconds , 8, 10 and losses. And I began to notice that on the Acer laptop (Windows 10) there are also strange things with the Internet, insanely low speed. Also, I pinged 8.8.8.8 from the Acer laptop. And the same picture, delays and losses. I turn off Wi-Fi on Macbook and everything is fine.On Acer, the speed increases and the ping is stable.Below are a couple of photos:

Here is a ping on macOS and Windows when connected to the network at the same time

Here is a ping on Windows when disconnected from Wi-Fi on a mac

I honestly can't figure out why. I also changed the country. I changed the wireless network mode to B, to G, to N. I set different channels with handles. I poked all the jumpers (switches) that are possible and the result is one. I found a lot of questions on the Internet on the forums about the bad Internet on poppies, but I did not find a solution to my question.

Who knows what the trouble is and how to defeat it, or is it a problem in the Macbook itself and cannot be fixed?

Answer 1

In general, I honestly do not know what I did and what ultimately helped. I put mikrotik back in place, reset the settings without leaving the default ones. Set up manually.

Screen settings mikrotik (Wifi)

I also dropped NVram and SMC according to the instructions of which there are a lot on the Internet.
Another problem was that when Macbook and Acer Laptop were connected simultaneously to the Wifi network, the pings were unstable (huge delays and losses). Deleting all files from this folder (/Library/Preferences/SystemConfiguration/) definitely helped. Then reboot and after that the ping went fine.
Well, here is a speed measurement on a macbook. At least as they say.

speed test

Answer 2

First, check if this router only has problems with the poppy.
And then, I have already written here several times, but I will repeat.
1) On an old poppy (I have 2013 late), my dir 300 was chopped off if I connected a mouse. BT 2.4 frequency matched with wifi.
2) wifi even if it supports n 300 mbit, it still works at n 150mbit frequency. I don’t remember exactly where, but poppies have such a feature.
Also keep in mind that your router is wildly old. If you need good wifi at home - well, buy a good router for your home. They will work for you for the next 10 years perfectly. At least for me, not one of them died of his own free will in 15 years.

Answer 3

I see two options, based on the router (it’s simple)
Or the poppy, when turned on, starts downloading updates, and thus stupidly clogs the entire WIFI, the router can’t cope
Or the poppy is too old, which connects according to the G standard, which again lowers all devices on the network "before this standard is outdated.
I would try to use an external modern wifi for a poppy and check
well, or check the Internet download when you turn on the poppy, if something is pumping, then how the problem will be solved)