The jitter on your upload was quite high, probably messed with your TCP/IP window scaling.
St. Ghislain, Belgium, EU (google)d144.21 Mb/s172.6±0.4ms0%1760
London, UK (linode)d238.13 Mb/s194.6±0.4ms0%1556
Amsterdam, Netherlands, EU (softlayer)d242.27 Mb/s173.7±3ms0%826
St. Ghislain, Belgium, EU (google)u117.56 Mb/s167.9±35.5ms-10
London, UK (linode)u119.28 Mb/s187.3±39.9ms-10
Amsterdam, Netherlands, EU (softlayer)u27.81 Mb/s171.5±38ms-10
EDIT: Same as the other guy, but he had more streams as well. 8/6 vs your 4/4