"Attacks on staff are not tolerated. " - absolutely agree. Unforgivable, but that would be the case also if it were another user wouldn't it?

How is it possible for a 'burst' which is higher than the line speed?

Because of the way various buffers operate in the hardware and software of the computer, including AV and firewall software.

So basically, all speed tests are an approximation?

More that all speed tests can be affected by other factors. Speed tests can't necessarily control things like caching. Theoretically a network device could do all the requests for data and dump them down to the client in one go in which case the speed test would have nothing for a while and then suddenly a massive spike.

EDIT: The speed test is actually testing every component in the chain and therefore it shows where individual components could be doing something to the traffic. You would have to remove all of those components to get a "pure" test.

Edited by ian72 (Wed 08-Jul-15 16:37:40)

Thanks for the clear explanation.

In reply to a post by wingco1:

So basically, all speed tests are an approximation?

As the others have said, depends on buffering etc. A few years ago it was very common for Kasperksy users to get download estimates many times faster than their lines: eg 120Mbps on a 20Mbps line. This was down to some curious interference that Kaspersky did (possibly to get big enough buffers to do a reliable check) that interfered with the 'natural' flow of the data and broke the assumptions made by speed testers at the time. The interference did not a make significant difference to real data on the line, somehow just to speed tests.

Edited by StephenTodd (Wed 08-Jul-15 18:09:28)