How can I improve the transfer speed on my home network?

I am looking for ways to bump up the transfer speed between my local computers on my home network. I have 3 desktop computers and they are all running Windows. One uses wired connection and the other two are using wireless connection.

Desktop 1

Wired connection
100 Mbps NIC (integrated, Realtek)
Cable type is Cat 5e
Cable length is < 20 meters
Windows Vista

Desktop 2

Wireless connection
300 Mbps NIC (USB 2.0, D-Link DWA-160 dual-band @ 5 GHz, Atheros chipset)
1000 Mbps NIC (integrated, Realtek, not in use)
1000 Mbps NIC (integrated, Realtek, not in use)
Proximity to router is < 10 meters
Windows Vista

Desktop 3

Wireless connection
300 Mbps NIC (USB 2.0, D-Link DWA-160 dual-band @ 5 GHz, Ralink chipset)
1000 Mbps NIC (integrated, Realtek, not in use)
Proximity to router is < 20 meters
Windows 8

Router

D-Link DIR-825
Wireless N
1000 Mbps integrated switch
Both 2.4 and 5 GHz bands are enabled
DD-WRT firmware
WPA2/AES encryption mode

I have a 10 Mbps dedicated Fiber-LAN connection to the Internet. That's exactly 1.25 MB/s. I can achieve this speed when I download something from the web, and beyond that. I can easily download at 1.3 MB/s from either one of the computers. I can upload with the same speed, and usually exceed that and peak out at about 1.7 MB/s.

Now, when I transfer a 250 MB file between two computers locally I can only get about 3 MB/s on average. How can I bump this up to at least 12.5 MB/s? As you can see, two computers are Gigabit-Ethernet capable, and one is only Fast-Ethernet capable. If they all operate at the slowest speed available, that would be 100 Mbps. I understand that this is only theoretical speed. But what's preventing me from achieving at least half of that? That would be 12.5 MB/s, and I would be happy with that.

Samir

Posted 2013-10-14T20:49:03.787

Reputation: 17 919

Note that MB/s != Mb/s. One megabyte (MB) is eight megabits (Mb) per second. – Blacklight Shining – 2013-10-14T20:52:20.900

1@BlacklightShining Yes, thank you for clarifying that. Let me just add that I am not mistaken. I know for sure I have slow transfer speed locally. I understand the difference in bits and bytes. I just don't like using the slash, e.g. "MB/s" so I use "MBps". Note the upper-case B. – Samir – 2013-10-14T20:54:19.577

You might want to convert everything to one or the other, to avoid confusion. (IMO, everything should be done in mebibits (MiB)—they're based on powers of two rather than powers of ten.) – Blacklight Shining – 2013-10-14T20:58:27.543

Your router may not be able to process data faster than the speeds you're seeing. Try just a cable between two PCs and see how fast it transfers. – Ƭᴇcʜιᴇ007 – 2013-10-14T21:06:43.373

possible duplicate of Why transfer speed over Fast Ethernet (100mbps I think) is only ~1.5MiB/s

– Synetech – 2013-10-14T21:11:48.597

@BlacklightShining, Sammy already accounted for units from the start, so that is not a point of confusion. – Synetech – 2013-10-14T21:12:38.757

@BlacklightShining Right! So how many "mebibits" per second is 10 "megabits" per second? I am using the units as they appear on network equipment and inside Windows. I have added the slash for MB per second. You won't confuse it with Mbps now. – Samir – 2013-10-14T21:12:50.570

@Sammy, I recently wondered about this issue. I transferred some files between two systems through my router and was confounded that they were limited to 1.5MBps (the meter showed a peak of 1.7, but it was 1.5 on average). While researching the issue, I found Jiew Meng’s question and considered editing it to provide more information instead of opening what would amount to a duplicate question. Then I saw your question which is the same. It seems this is not a defect, but a limitation of something. Hopefully we can find a solution or work-around.

– Synetech – 2013-10-14T21:17:22.023

2When you transfer a file between two wireless machines, all the data has to be sent over the wireless link twice, once from the source to the access point and once from the access point to the destination. The acknowledgements have to use the same channel, and it takes time to "turn the channel around" when a device switches from transmitting to receiving. Take your 100Mbps (which is likely roughly your effective WiFi bandwidth as well) and divided it by 3 to account for these costs and you get about 4.2MB/s -- your expectations are unrealistic. If possible, wire all devices. – David Schwartz – 2013-10-14T21:41:49.173

@DavidSchwartz Would it help to add a dedicated switch into the mix? Instead of using the built-in switch of the router? I'm thinking maybe the router can't process the data fast enough, locally, as opposed to externally (WAN throughput). I think you have touched on that here. So I was thinking maybe a separate AP and a dedicated switch behind the router and the Internet connection? Is it worth it? Or would that be just adding pancake on top of another pancake? I mean a wireless router should already have this capability. – Samir – 2013-10-14T21:52:59.500

@Sammy How could adding an extra hop possibly help? You would then have to go from the router's WiFi to the router's CPU to the router's switch (to get to the router's Ethernet port) to the external switch ... That would be very slightly worse. The router has a hardware switch between its Ethernet ports. If it's router load, it's with the WiFi-to-switch part, not the switching itself. – David Schwartz – 2013-10-14T22:02:28.590

When you transfer a file between two wireless machines… take your 100Mbps (which is likely roughly your effective WiFi bandwidth as well) and divided it by 3 to account for these costs and you get about 4.2MB/s Already considered that; it doesn’t explain it. I transferred between one wired and one wireless. Even dividing 54Mbps (802.11g) by three still gives 2.25MBps, not 1.5. Something else is “bottlenecking”. – Synetech – 2013-10-14T22:13:44.647

Answers

According to some testing (2.4 GHz only), a DWA-160 can send and receive 20 - 60 Mbit/s. (2.5 - 7.5 MB/s) Certainly a far cry from the theoretical 300 Mbit/s. The speed you get is on the low end of the range, but still plausible.

A 100 Mbit/s ethernet link should in theory be able to put through 12.5 MB/s. Using netcat (windows version here) as a transfer program on both ends of a point-to-point link I can usually get up to around 11 MB/s.

So as Ecnerwal says, wired beats wireless. :-)

These USB dongles have limited antennas and orientation of the antenna seems to be able to make a significant difference. Try putting the dongle on a USB cable and vary its orientation.

Roland Smith

Posted 2013-10-14T20:49:03.787

Reputation: 1 712

Wires beat wireless 7 days a week in terms of moving data, for a multitude of reasons. Could be worth trying a couple of cables to the router from the current wireless connections. USB WiFi Dongles could be crimping your style even more than a regular WiFi, and regular WiFi is hardly ever anywhere near the "claimed" top speeds. The D-Link product Page says it's USB 2.0 (480 Mbit), so it's certainly not gigabit capable - and wireless N is also not gigabit capable (and rarely, if ever, even 300Mbit capable.)

A "regular" WiFi Connection would be one connected to a bus that does not, itself, throttle the potential speed. Built-in and/or PCI versions generally meet this criterion. However, given actual rates of throughput on most wireless links, USB2.0 may be more than adequate, so long as the USB port it's plugged into is also 2.0

You might also try (quicker and easier than buying new cables, perhaps) using the 2.4 GHz band, since you have dual-band devices. In my observation, when passing through walls, 2.4 GHz tends to get better actual data rates than 5 GHz, despite all the hype for 5GHz.

Ecnerwal

Posted 2013-10-14T20:49:03.787

Reputation: 5 046

Will Cat 5e do or should I opt for Cat 6 if I'm getting new set of cables? If I am not mistaken, Cat 5e should handle up to 100 Mbps, right? I will try this as soon as I get new cables and I will also try connecting a single cable between two computers, just to see how that goes. – Samir – 2013-10-14T21:42:00.110

What is regular WiFi? Do you mean like integrated WiFi in smartphones and laptops and such? – Samir – 2013-10-14T21:43:27.620

Cat 5e is also the standard desktop cable for gigabit connections. Cat 6 and Cat 7 are mostly used for fixed cable installations. – noggerl – 2013-10-14T21:47:21.437

Cat5e is perfectly adequate for gigabit. Cat5 is plenty for 100Mbit. Cat6, 7 gains you exactly nothing for Gigabit. – Ecnerwal – 2013-10-14T21:48:34.663

Thanks for the correction about Wireless N and USB 2.0 transfer speed. I will have to buy a new set of Cat 5e cable tomorrow, do some tests, and report back. – Samir – 2013-10-14T22:05:37.713

This might sound like a silly question, but how does bending the cable too much or stepping on it affect the performance, really? I once learned that a regular Ethernet cable should never be bent more than like 45 degrees or so, roughly like a Tennis ball. Bending it more supposedly changes its electromagnetic characteristics and that affects performance. I come to think of it... some of my patch cables are rolled up real tight to conserve space. It might be affecting the performance without me knowing it. – Samir – 2013-10-14T22:09:40.400

1The bend radius should be at least four times the outer diameter of the cable. This is the rule for category 5, 5e, and 6 – Nikola Dimitrijevic – 2013-10-14T22:14:53.107

I just created a QoS rule on my router for LAN port 1 and set priority to high and my large file transfers improved quite dramatically. Your scenario is very much like mine. A wired Vista PC transferring files from a wireless laptop.

user529568

Posted 2013-10-14T20:49:03.787

Reputation: 1