I also experienced significantly slow and unstable international traffic in the past few weeks, especially when viewing websites in Asia and China.
This morning it was even worse as I basically couldn't load any Chinese websites.
Meanwhile my university connection can access them smoothly.
I've done some traceroute for troubleshooting.
China:
Singapore:
Japan:
UK
From my analysis it seems there are issues connecting USA and China via gtt.net networks. Not sure if that's the actual problem.