Internal Network Speed Question

[RickL]

Hi Guys,

Now I have my new router up and running I thought it be best to back-up a shed load of data to an off-site HDD. So, not really a question about individual application as I see this question being generally network wide. Almost regardless of network connection speed, I seem to only be able to hit a maximum transfer rate of 15-20 mb/s depending on which device despite being connected at nearly a giga-bit mbps.

Not that I'm complaining because for an internal home consumer network, I still see this as being above average and it works very well but it got me wondering... 

 

Example:

Currently I have an external USB 3.0 Seagate drive using SATA > USB (standard cable) plugged in to the USB 3.0 port on the TP-Link Archer C9 Router, which is then copying back and forth to my slave / server PC which is connected via Wifi at around 877 Mbps. Which on paper just based on those facts should give around a 100-110 MB/Sec transfer rate, as you can see, im hitting some 15% of that.

The only thing that I can see actually being the bottle neck would actually be the router CPU, but that is just a guess. (The actual PC Hard-drive we are copying too / from is a WD Red Drive, not that it matters as Iv tried it on the SSD 840 Evo also).

 

What do you think?

 

[mikat]

you will not always reach your maximum speed your wifi card is capable of because there is interference, just like you don't get 100% of your advertised speed on wifi.

[RickL]

I understand that, however, that would suggest that distance / interference / connection speed would play a large factor which in this case, it does not... not a huge affect anyways. Even if I'm sat right next to the router (which I am right now), the speeds remain the same. Which makes me think that something else is the bottle neck apart from the wireless connection itself.

[Trikein]

I think the bottleneck is the router itself, between the WLAN and USB 3.0 interface. What partitioning are you using on the flash drive? As per here, 

 

TP-LINK Archer C9	Linksys WRT1900AC	Linksys EA6900	NETGEAR R7000	ASUS RT-AC68U
Processor	Broadcom BCM4709A	Marvell MV78230	Broadcom BCM4708A	Broadcom BCM4709A	Broadcom BCM4708A
FAT32 Write (MBytes/s)	22.8	28.7	14.5	24.8	11.8
FAT32 Read (MBytes/s)	28.7	31.0	21.0	27.8	24.0
NTFS Write (MBytes/s)	17.2	30.1	17.2	27.9	23.7
NTFS Read (MBytes/s)	23.9	30.8	21.2	27.9	24.2

 

 

With NTFS you will see Read/Write of 23.9MB and 17.2MB. Also, what HD do you have in the slave PC? You might be further bottled necked by the OS. I would try to isolate the greatest bottleneck by testing different transfer rates one at a time. Like WAN > USB and USB > LAN and LAN > LAN. Newer routers have separate CPU just for the USB interface to increase speeds. C9 is a great router, just USB transfer speeds is one of it's weaknesses. 

[RickL]

That makes PERFECT sense then. Many thanks for that dude, clearly identifies my bottle neck. Applicable to me NTFS Write Speed 17.5 MB/S Max (I have seen it go this high a couple of times but settles as per above). At least now I know. Its not a function to be used all that often by me so im not that bothered by it but wanted to understand it further.