Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?

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Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?

This thread has been locked for further replies. You can start a new thread to share your ideas or ask questions.
Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
2023-12-20 13:46:22
Tags: #nas
Model: Deco M5  
Hardware Version:
Firmware Version: 1.7.3

TL;DR: As soon as my TP-link Deco M5 is added to my network the wired(!) transfer speed between PC and Synology NAS drops down to max 355kb/s.

 

I recently expanded my network with a few more Deco M5 units and connected some hardware in a different location in my house.

 

Since then, for my Synology DS220+ NAS I have achieved a maximum (download) speed of exactly 355 kb/s in a wired connection with my PC. Resetting etc. didn't change anything. The NAS is next to my PC and they are connected to each other by ethernet cable via a switch. The switch is connected to the rest of the network via an ethernet cable to an Deco M5 unit that picks up the wifi signal from the ground floor. I added a picture below of the setup. The WiFi speed on the PC (and other devices) is excellent and way above 100 MB/s as expected.

 

After a lot of researcg, it turns out that the Deco network is the cause of the low speed from NAS to other units (via Ethernet cable or WiFi). As soon as I remove the network cable from the M5 unit to the switch (and the NAS and PC are only connected to each other and not to the rest of the network), I suddenly get download speeds approaching 80-100 MB/s. So the limit on the speed comes from the broader network via the Deco units.

 

I have checked all the settings in the Deco app but I cannot see where the cause could be. Does anyone have an idea why my Deco network is interfering with the (wired) connection between PC and NAS? And how to solve it of course.

 

Layout:

 

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#1
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7 Reply
Re:Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
2023-12-20 18:45:59

  @Mycroft is there any QoS settings enabled?

 

 

Deco App -> More -> QoS

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#2
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Re:Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
2023-12-20 19:25:34

  @richpriest 

 

Under QoS I see three things.

 

Bandwidth is set based on an internet speed test.

High priority mode is set to standard.

A few devices have been set with high priority among which the NAS.

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#3
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Re:Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
2023-12-20 19:28:09
Try setting the limits to 1000Mbps manually and see if it changes anything.
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#4
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Re:Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
2023-12-20 19:48:59
I set the limit of the upload and download speed to 1000Mbps and it did not change anything. The wired transfer speed between PC and NAS stays limited at 355kb/s.
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#5
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Re:Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
2023-12-20 20:00:33

  @Mycroft what switch do you have?

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#6
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Re:Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
2023-12-20 20:11:46

  @richpriest 

 

    

The switch is an TP-Link LS1005G.

But I doubt that is the issue, because when I disconnect the Deco M5 from the switch then the PC and NAS (via switch) transfer wired much much faster (more than 90mb/s).

 

(Thanks for thinking with me what could be the issue)

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#7
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Re:Problem: TP-link Deco M5 totally limits wired transfer speed from PC to NAS (Synology DS220+)?
2023-12-20 20:40:28

  @Mycroft I asked as I recall an issue with Dlink (I think) switches when communicating with TPLink devices, but obviously not here.

 

Is the Synology a single NIC device? If not, does it perform the same with a single connection?

 

I am running out of ideas at this point, I must admit.

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#8
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