RT-AC86U Slow NAS Access

[Stepalex]

Hello,

I have Synology DS1813 NAS, connected via ethernet to RT-AC86U running on Merlin 384.15, previously on 384.14. Only SMB is switched on my NAS.

If DS1813 is connected directly to my PC, I am getting full 1 Gbps speeds (about 115 MBps read and write).

If DS1813 is connected via RT-AC86U, I can get a maximum of 55 MBps read and 45 MBps write if testing from Win 10 machine, 22 MBps write if testing via Mac.

As I am getting full speed when connected directly, and then tested both Win 10 and Mac machines, all other chain links are eliminated (NAS, ethernet cable, my PC) and that leaves the issue to my RT-AC86U.

Jumbo frames are switched on, whereas there is no 'NAT' setting in my RT-AC86U for some reason.

Any thoughts what may be causing those slow speeds?

Thanks.

 

[ColinTaylor]

Check the Ethernet port link state at Tools - System Information. It sounds like your connection to the NAS might be operating at half-duplex.

Disable Jumbo frames for testing purposes as that can sometimes cause more trouble than it's worth.

 

[Stepalex]

It's full-duplex, and I've tried with jumbo frame rates off too

 

[Stepalex]

Any ideas?

 

[Magnus_SL]

Any ideas?

Weird comment from me but could it be that your are connected to Ethernet by wire AND wifi at the same time? Reason for asking is that your Mbps speeds look very much like "fast" wifi ac speeds. 115 mbps equals pretty much 15 Mb/s and that is typical with your setup when on wifi. On cable/wire with 1 gigabit maximum (net) speed is around 110-115 Mb/s (circa 900 Mbps).

 

[Stepalex]

Nope, Synology is connected by wire only, and my PC/Mac are connected by Wi-Fi only too when I experience low speeds.

In the example above, I get 115 MB/s (=circa 900 Mbps) if I connect my PC to Synology directly by ethernet.

 

[ColinTaylor]

Nope, Synology is connected by wire only, and my PC/Mac are connected by Wi-Fi only too when I experience low speeds.

Sorry, I thought you were saying that your PC, Mac and NAS are all connected to the router with Ethernet cables (i.e. no WiFi).

In the example above, I get 115 MB/s (=circa 900 Mbps) if I connect my PC to Synology directly by ethernet.

Again the assumption here is that when you said "directly by ethernet" you meant with a single cable between the PC and NAS (i.e. not connected to the router in any way, and no WiFi)

Are you now saying that slowdown only occurs when the PC or Mac is connected to the router over WiFi?

 

[Stepalex]

Are you now saying that slowdown only occurs when the PC or Mac is connected to the router over WiFi?

Synology via ethernet > PC = 900 Mbps

Synology via ethernet > RT-AC86 < PC via wi-fi = 400 Mbps

Synology via ethernet > RT-AC86 < Mac via wi-fi = 160 Mbps

Ie if RT-AC86 is used in the 'chain', speeds are much slower.

I cannot fault wi-fi in my Mac/PC as can get circa 900 Mbps from one to another.

 

[ColinTaylor]

Synology via ethernet > RT-AC86 < PC via wi-fi = 400 Mbps

Synology via ethernet > RT-AC86 < Mac via wi-fi = 160 Mbps

So what speeds do you get with:

Synology via ethernet > RT-AC86 < PC via ethernet = ???

Synology via ethernet > RT-AC86 < Mac via ethernet = ???

 

[Marc66]

Can you also please use the same units when reporting/comparing? Mbps or MBps are not the same


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