Question AC/Cable/Router Tricky Question

Aug 14, 2019
Good day to everyone,
I have a fiber connection which is going to my modem, then to the ISP's router and to my own personal router. So far so good. The problem is that I only get my contract speed (300 Mbps) when using one of the two wires (the one from my personal router). When using WiFi I only get 100 Mbps tops, even though I'm on AC. Both my laptop and router are competent enough, but when I put the cable in the router it only sees it as 100 Mbps, even though THAT SAME CABLE gives me 300 Mbps when hooked to the laptop. I'm set on DHCP on both routers if that's of any help.

My question is, what is wrong with it? Why can't I get close to 300 Mbps/30 MB/S speeds on my AC Wifi and why is it showing only 100 Mbps when plugged in the router?


DHCP should be enabled only on one router - not both.

Which router is providing wireless?

And are you sure that the ISP's router is only a router and not a combination modem/router?

Wired is inherently faster than wireless.

So if internet/network connectivity goes from wired to wireless to wired - then wireless speeds will prevail.

Update your post to include the makes and models of modems and routers.

Edit/correct the following line diagram as necessary:

ISP ---fiber---> Your modem ---Ethernet--->[WAN] ISP Router[LAN] --- Ethernet--->[LAN]Personal router [LAN] ---Ethernet---> Wired devices and ~~~ wireless ~~~> Wireless devices.
Aug 14, 2019
Hello and thanks for the reply!

To be honest, I didn't know that. I had DHCP enabled on both and it worked (minus the speed). If I try to do my original plan, which was to set the personal router as a repeater, nothing worked. I'm currently using wired at the moment.

It goes like this:
ISP ---fiber---> WAN]Modem/Router combo[LAN]---Ethernet--->Laptop
Right now the ISP Combo is giving the WiFi but it's an old design, mine is much closer to my devices and also has 5GHz and AC.
I want to go like this:
ISP---fiber--->[WAN]Modem/Router combo[LAN]---Ethernet--->Personal router.
From this I can take WiFi or have the option to plug the cable if I find the WiFi not up to par.
What I want to do is modify the last step to be via WiFi so I don't trip over the cable all day. It is slower, inherently so, but at about 30MB/S it should make no difference. I am the only guy on 5 GHz, AC, distance about 5 meters, no walls between. Should work like a breeze.

Anyway, my router is a D-Link DIR 809 AC750. It displays 433Mbps in Windows, as advertised on the package. However, in its settings page it shows the WAN connection as being 100Mbps so that's what it's giving to the WiFi. The ISP's router/modem is a cheap POS, AN5506-02-FG is the model number, no manufacturer. It's set on PPPoE for WAN and DHCP for LAN.

I hope this makes sense. The gist of it is that I'm not getting 300Mbps to my router from the CAT5 even though it has no problem giving that straight to the laptop. And no, it's not a MAC issue, if anything it should be the laptop not working properly since it's the newest equipment on the block.

Thanks for your time!
Last edited:
These type of routers should not really be sold without large disclaimers.

To a point they are admitting that the wifi speeds they quote are lies....all router manufacture use this deception though. You most times will be lucky to get even 100mbps on even 802.11ac. Even if you have really fancy 802.11ac and matching end devices (which are very rare since they use 4 antenna) you might get 300mbps using it at a reasonable distance.

But all the above is secondary the reason you can not get above 100mbps is the LAN and WAN ports on your router are only 100mbps. You need a router with gigabit speeds.

In addition the ISP box is really strange, I have looked this up before when other people ask. It has 2 lan ports but one is 100mbps and the other is gbit. You must be very sure you are always using the gigabit. I am assuming that is the port you plugged your laptop in to test.

So step 1 is going to be to buy a device with gigabit lan and wan ports. The wifi speed you get is going to be hard to predict. I seriously doubt you are going to get 300mbps so take that into consideration, if you can live with the wifi speed you could put a gigabit switch between the 2 routers for ethernet connected device you need the full 300mbps bandwidth.
Aug 14, 2019

Thank you for the reply. I found out by my stupid self that the WAN port is 100Mbps. Why sell something like this? Why give 433Mbps WiFi when you know you won't be able to deliver it because of poor WAN speeds? This is the last time I buy D-Link garbage. As for the ISP's doodad, yes, I am using the Gb one. It goes from there straight to my laptop which gives around 280-300Mbps wired, no problem. The culprit was my router. Imagine that! 40 bucks for such a piece

Thank you for the help!
It is even worse, you could have gigabit ports and you will never get the 433. To get this number they add the transmit and receive speed together. This would be like calling a gigabit ethernet 2gbit. Thing is ethernet can actually transmit 1gbit and receive 1gbit at the same time. wifi is half duplex.

In addition of overhead and in inefficiencies cuts this a lot. Even if you put the end device directly on top of the router you will be lucky to get 100mbps.