Question My Wifi Router wont stream fast


Jan 4, 2010
Hello all! So I have setup a Plex media server on a Synology DS918+. I am having an issue where the bottleneck is the LAN. The wired connection in the room with the 4k TV is limited to a 100mbps lan, due to Direct TV and having to use a "Broadband DECA". Some of my 4k HDR movies are requiring as much as 130 mbps in order to not have studdering and or buffering. My WIFI router is an ASUS RT-AC88U which is advertised as being able to handle 3gbps on the 5G. I get way more buffering over WIFI than the DECA which is usually averaging 90 mbps. WHY am i not able to stream media over my wifi network like i am supposed to? It makes no sense. Back when I had cable internet, it was able to maintain a 300mpbs internet speed with no issues. My NAS is connected to the wifi router via 2-1 Gigabit link aggregation. I have given the NAS and the plex media player client both Static Ip addresses, and put them both top priority in the QOS, as well as selected Media streaming as the top priority in the QOS. AM I MISSING SOMETHING???

Please help me. Thank you for your time
Your largest issue is believing the lies being told by the router manufactures on wifi speeds. They do stuff like add multiple radio speeds together when the end unit can only use one radio. You will get only a tiny fraction of those speeds in real life installs. This ignores the most important issue limiting top speed and that is all your neighbors competing for the same radio bandwidth. If live in a area with lots of wifi usage it will greatly limit your speeds. You likely get more consistent throughput on the physical connection.

I have all kinds of concerns over a bunch of stuff you included.

Directtv deca only runs over coax and simulates ethernet. If you have real ethernet it will run at gigabit speeds if you plug it into gigabit ports. If you run your network over the deca you are sharing bandwidth with the directtv.

You should need nowhere near 130mbps to stream video you have something wrong with your encoding if you do. h264 needs about 40mbps and h265 needs about 20 and h265 is said to actually be better quality. Be very sure it is not your server itself causing the buffering because it is converting files or something.

QoS only really applies to the internet traffic and it works poorly even for that traffic. The concept of QoS on wifi is completely invalid since there is no control over the end stations and it is half duplex. This also ignores the even larger problem of your neighbors could careless what you have set anything to they will just try to use the wifi and stomp on your signals.

The aggregated connection to the nas likely does nothing at all. Because of how 802.3ad (link aggregation) select paths it generally does not do much in a home install. It many times puts all the traffic on a single cable and leaves the other unused. It was primarily used for a large server than had many hundreds of client machine access it. It can cause data stalls and studdering at times because of compatibility issues between equipment. It is best not used because it provides little benefit even if functioning correctly.