I pulled this over from the How I Love Windows thread because it's good info for both Windows and Mac. I know, some of you experts will tell me you already knew this. 
What I've learned recently.
2.5 vs 5G Wifi
You want that fast new 5G router for it's blazing speeds? Hint: 5G SUCKS unless you are very close to the router in the same room. My setup is an office in a separate room with my computer about 35' from the router. 5G is 2 bars, and 2.5G is 4 bars. On Wifi, my download performance is best using the 2.5 network. Note, these types of routers offer both 2.5 and 5G speed. My understanding is that 5G is twice the speed at half the bandwidth.
Of note: My 5 frick'n year old MacBook Pro downloads data faster than my late 2013 PC Gaming rig over wifi from my office. Why do I love my Mac? Oh, yea...
https://en.wikipedia.org/wiki/Power_over_Ethernet
Power over Ethernet
Those little boxes that use your house wiring system to deliver ethernet from your router to your computer in that other room. Nope, it comes no where close to real ethernet speeds, but it's not that expensive. In my example I have 200Mbps Internet service in my house. When I plug my MacBookPro into my router, or when I run a 40' ethernet cable from my router to my PC, both of these download at 200Mbps.
However, when I hook up PC to a TP-Link TL-P4020P Passthrough Powerline box, one at the router and one at the computer both plugged into the wall, I get a connection, the link speed is 100Mbps, but the actual download speed is 1/2 that or 50MBPS. Over Wifi using an Archer T9E wifi adapter over the 2.5 Ghz network, I get about the same speed, but I've actually gotten up to 70Mbps via wifi. There are lots of things going on outside your house.
So the moral of this story is if you don't have wifi in your computer or due to arrangement of your computer to a router, wifi is not practical, POE is a viable alternative. The only warning I've read is that the circuits where you plug these devices in must go through the same CB panel. In an apartment, it may not work.
What I've learned recently.
2.5 vs 5G Wifi
You want that fast new 5G router for it's blazing speeds? Hint: 5G SUCKS unless you are very close to the router in the same room. My setup is an office in a separate room with my computer about 35' from the router. 5G is 2 bars, and 2.5G is 4 bars. On Wifi, my download performance is best using the 2.5 network. Note, these types of routers offer both 2.5 and 5G speed. My understanding is that 5G is twice the speed at half the bandwidth.
Of note: My 5 frick'n year old MacBook Pro downloads data faster than my late 2013 PC Gaming rig over wifi from my office. Why do I love my Mac? Oh, yea...
https://en.wikipedia.org/wiki/Power_over_Ethernet
Power over Ethernet
Those little boxes that use your house wiring system to deliver ethernet from your router to your computer in that other room. Nope, it comes no where close to real ethernet speeds, but it's not that expensive. In my example I have 200Mbps Internet service in my house. When I plug my MacBookPro into my router, or when I run a 40' ethernet cable from my router to my PC, both of these download at 200Mbps.
However, when I hook up PC to a TP-Link TL-P4020P Passthrough Powerline box, one at the router and one at the computer both plugged into the wall, I get a connection, the link speed is 100Mbps, but the actual download speed is 1/2 that or 50MBPS. Over Wifi using an Archer T9E wifi adapter over the 2.5 Ghz network, I get about the same speed, but I've actually gotten up to 70Mbps via wifi. There are lots of things going on outside your house.
So the moral of this story is if you don't have wifi in your computer or due to arrangement of your computer to a router, wifi is not practical, POE is a viable alternative. The only warning I've read is that the circuits where you plug these devices in must go through the same CB panel. In an apartment, it may not work.
Here's a question about increasing wifi speeds using Windows 10 although I think the principles would also apply to Macs. As part of cutting the cable (kinda lol) I increased my home internet speed to 200MBPS through my cable company.
When I hook my PC directly to the router with a 40' ethernet cable, I get a download speed from SpeedTest.net of 200Mbps. However It's not convenient to have an ethernet cable connected to my router so I usually rely on wireless.
Before I was using a TL-WDN4800 Wireless adapter on my PC and from my office about 35' from the router in another room, I was getting a download speed of 50Mbps. It does not appear that this adapter is supported by Winows 10, so I purchased an Archer T9E plus added a TL-SNY2408C Antenna thinking this would improve connection strength and download performance. With this device, under Network Connections Wifi shows a status of 215.Mbps, however when I run the SpeedTest, I get about 62-70Mbps.
I also purchased a TL-PA4020P Passthrough Powerline Starter Kit (run's ethernet though your house wiring) hoping this would match performance of the ethernet cable directly connected. When connected with these devices in the Network Connection, the status shows a speed of 100Mbps, but when using the Speed Test I'm getting about 61Mbps. This is supposed to be the faster connection, than wifi, but for downloads, it's slower than my wireless.
Any thoughts on this? I might end up running an ethernet connection directly to my PC, but I'd like to improve speeds with the TL devices instead so I don't have to crawl around in the attic when it's 150°.
For Wifi, I'm going to buy the 50' extension cable for the desktop antenna and run it closer to the router, maybe that will help a little. Question: When using the desktop antenna, does it matter which connector is used on the wifi adapter (that has 3 antennas)? And does it matter if the other 2 antennas are left on or should they be removed?
Also I'm a bit confused, my router is a Netgear N900, dual band. I have both networks activated and I thought a 5G connection was supposed to be faster, but when I connect to the 5G network with wireless it only shows 2 bars, but when I connect to the other network (2.5ghz?) I get a 4 bar connection?
Any insight will be appreciated. I game a lot so the extra speed is important. If worse comes to worse, I'll wait until winter and run a ethernet cable up through my attic an down to my office when it's cooler .