its ok for me, alot of these weird results are related to software issues, sometimes caused by a/v software intercepting the traffic, other times might be down to browser been used, or lack of cpu grunt messing up packet timings,even things like line bonding which causes packet ordering issues may even have an impact.
For me one speedtester that started giving issues on the upstream was the dslreports test, but in the advanced settings page you can change the type of method used to transfer the data and that fixed it, which proves software implementations can cause bad results.
For a proper simple test maybe just run iperf instead?
