500 Mbit/s powerline network, only 3.5 Mbyte/s transfer speed?

Solution 1:

That's not wireless... those adapters are using your electrical wiring as a medium to transfer the data.

This technology is known for being less than reliable, especially if the two ends of the connection are on different circuits. More than that, a lot of power lines have a lot of noise in the wire that can significantly reduce that actual vs theoretical data throughput.

Now let's look at some other limiting factors. If either computer only has a 100Mbps card, that is as fast as you'll go for the transfer. We also need to mention the uppercase B in MBps vs the lowercase b in Mbps. Whenever you see a lowercase b, you need to divide the number by 8 to get a better idea of how many bytes (vs bits) you can transfer.

So a 100Mbps link from the computer could at most supply your powerline adapter at 12.5MBps, and a certain amount of additional loss is normal for noise, collisions, and TCP overhead. The speed at which your source hard drive is able to read the data may be a factor as well, especially if you're moving data from an older computer to a newer one (which a 100Mbps adapter would suggest). One more potential limitation is the duplex setting of the connection. Most wired connections use two pairs of wires to allow both sides to transmit and receive at the same time. It's possible and even likely that your powerline adapter is only half-duplex, and cannot send and receive at the same time. This will result in more packet collisions that will further slow the transfer. Now factor in high noise in your powerlines, and 3.5MBps seems downright reasonable.

Solution 2:

No. 3.5 isn't too bad.

First, make sure you note whether you're getting 3.5 MBps or 3.5 Mbps. The upper- or lower-case B makes a difference of a factor of 8. Big "B" stands for "Byte", little "b" stands for "bit". There are 8 "bits" in each "Byte", hence the factor of 8 thing. Most internet connections and network connections are measured in "Mega-bits per second" while most file transfers are measured in "Mega-Bytes per second". Just noting, the Powerline adapters use the little "b" in their spec, as is normal for network connection speed ratings.

Then there is network overhead: other things the network has to use to keep the connection working right. This can account for quite a bit of your available bandwidth.

Next, while the Powerline adapter may be capable of 500Mbps, what it actual gets is very very dependent on the quality of your home electrical wiring. Unless the house is very new, has incredibly good wiring, and there are no other electrical junctions, circuit breakers, or large appliance in the circuit between the devices, you're highly unlikely to get anywhere near 500Mpbs total throughput on your network.

Take for example my very nice Gigabit (note: it's not GigaBYTE) network here are work. Transferring between two servers right next to each other on the same switch, I'm fortunate to be 100MBps actual throughput in file transfer speed, which is pretty good, because these servers are each connected to 4 Gigabit ports on that switch.

So, all that to say you're probably seeing an OK network speed.

Solution 3:

One of your computers is probably only 100 Mbit/s. After overhead, an ideal connection will get you about 10 Mbyte/s. Your power line adapter probably isn't ideal.

I don't think your numbers are totally off from reality. Up to 500 Mbit/s is certainly under ideal conditions which probably don't exist in reality.

Solution 4:

A couple of quick things that helped me pick up speed.

1. Make sure the plugs are on the same side of the breaker box
2. Make sure your plugs are wired the same.. EX. My speeds were really slow. Then I turned one of my adapters upside down. Speeds doubled.. Something about the phase.
3. Make sure your plugs aren't loose, I replaced both of my actual plugs. This just seemed like common sense for old houses/plugs

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