questionsis downloading large files onto an external drive…


Technology may have changed since I last knew anything about anything, but files are always downloaded onto your internal drive, then the OS will progressively move it to the external.

Inefficiencies do seem to affect download speed, however... So I suppose it's a theory worth testing. Try downloading to the internal, for a while, and see what happens. If you don't notice a consistent difference, I'd imagine the problem is elsewhere. Computer/download-manager/wifi/cable/router/modem/cable-line/cable-company/download-source/ect.. (Bear in mind you'll never get what your ISP claims you'll get. I think Comcast claims I'll get 20-someodd Mbps, but I'm psyched when I get 1.5 in a single download.)


The USB 2.0 link is what's limiting your speed. USB can only max out at 60 MB/s and it can't fully utilize that due to overhead and other stuff.

If you connected it through different means such as a SATA cable and plugged it into your motherboard making it internal, you would see much faster speeds. An e-sata connection (some computers/motherboards have these) would also be an improvement.

So I'd move it inside if you're the slightest bit tech savvy. You just need a SATA cable to plug the HDD to the motherboard and connect a SATA power cable from your PSU.

edit: or downloading to an internal drive would indeed be faster, then you could move the files over, but you'd have the same transfer speeds as you're still using usb 2.0

another edit: Also a thing about advertised download speeds. ISPs advertised in speeds of Mbps, megabits per second, but most everything else is in bytes. There are 8 bits in a byte, so a 18 Mbps connection would have a max download speed of 2.25 MBps


@brad3326: Almost right.

Absolutely, the speeds are listed in mega-bits per second, and there are 8-bits per byte.

We differ on the extra overhead created by packet headers, odd sized packets, dropped packets and ATM framing. Since all the bytes get packaged into tiny bundles with addressing info, port numbers, error correction and data info, there is extra overhead consumed. Data does not always fit evenly into packets so the overhead is not a constant ratio.

Bottom line, you may have to divide the Mb/S by a factor of 9 or 10 to get a better estimate of effective MB/S reception speed.


Hmm -- I don't want to disagree with some of the other comments, but I think there is more to the story.

Technically, a USB 2.0 port is much faster than your internet connection (at 480 Mb/S). I don't believe that's the issue. I get large ISO files via torrent and they consistently max out my internet connection at about 170KB/S or 1.6Mb/S. They are saved to an external drive with no problem.

What is unclear, is whether you have other issues creating a choke point.

For example, you think you are using USB 2.0 capable gear, but USB will automatically fall back to a slower USB 1.0 speed (1.5MB/S) if you use a hub or certain extension lines.

1st check. Find a really large file on your hard drive. Copy it to the USB drive and then back. Time it each way and calculate the effective transfer speed. Is it close to 10-15 MB/S?

2nd, if you have anti-virus software that scans files while reading or saving, turn it off and test the difference.



Because of operating system overhead and disk transfer rates, it is rare to see large files written any faster than 10-15 MB/S. You would need an ideal setup to achieve the raw (burst) test speeds you see in vendor specs.

But if you copy to the USB drive and the speed is lower than 4-5 MB/S then something forcing the USB ports to run in v1.0 mode. See the link above.

I do agree, the simple fix is to download files to a TEMP folder, then transfer a copy to the USB drive later.

However, if your downloads are still speed limited, either your ISP is giving you sub-standard speeds or throttling you, or your download source is limiting you, or your machine has something else affecting the bandwidth.

Guessing what is a bit beyond the scope of this forum.