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Why difference between DSL speed tests?
ritz3
Enthusiast - Level 1

I have the basic High Speed DSL account that Verizon is representing as being capable of .5 - 1 mbps.  But I've never gotten anything more than 120 kbps download and 35 kbps upload speeds in 'real world' file transfer tests.

However all the online speed test websites I've used, as well as the one the Verizon repair technician used when he came out here, return results from 750 kbps - 1 Mbps down, and 275 kbps - 400 kbps up.

I've done my own download speed tests on 3 different PCs via FTP, Bittorrent, and HTTP protocals, and none ever get more than 120 kbps down.  Firewalls can limit transfer rates, but I've shut them all down, and still only get a max of 120 knps down.

Can anyone explain why there's such a disparity between the speed test results from all these various Inet speed test websites, and my actual real world transfer rates?

Thx

ritz

Re: Why difference between DSL speed tests?
smith6612
Super User
Super User

It sounds like you are confusing Bits from Bytes, in this case, Kilobits from Kilobytes. Many speed testing sites use Kilobits to measure the throughput (Often represented as kbps) whereas a lot of programs transferring data reference the speed in Kilobytes (Represented as KB/s or kBps).

If you're getting 1000kbps solid on a Speed test, you should be getting around 125KB/s of throughput. On upload, if you're hitting 340kbps of throughput, you should be getting around 42.5KB/s of throughput.

Re: Why difference between DSL speed tests?
ritz3
Enthusiast - Level 1

DOH!  ... Of course.  I used  to be quick on the draw on that one... but that data storage cell needs dusting off a bit I guess,

Thanks Smith6612

Re: Why difference between DSL speed tests?
smith6612
Super User
Super User

No problem. It happens to the best of us 🙂

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Re: Why difference between DSL speed tests?
weedeater1
Contributor - Level 3

As an FYI, we used to use a factor of 10 going from bytes to bits rather than a factor of 8. Start bits, stop bits, parity, etc.  I suppose it means less with large frames, but there is still some overhead.