The GFW is apparently quite sophisticated[1] and likely uses machine learning among other things such as TLS side channel attacks.

[1] http://blog.zorinaq.com/my-experience-with-the-great-firewal...

In Beijing currently. I set up a SOCKS proxy through an EC2 instance and it seems to be throttled after 10 minutes of use -- to the point that Edge on my smartphone is faster.

Unrelatedly: I was very surprised that the GFW lets through Amazon web traffic.

China throttles lots of foreign websites that it doesn't block. It wouldn't be surprising if they target all foreign ssl traffic for throttling too.

I wish I could. I don't see how CHina could capture SSL traffic in terms of inspection, but my networking knowledge is limited.

Re: higher SSL latency, my best guess is either under-provisioned routing hardware or intentional throttling.

More generally, the network topology in mainland is a lot different than networks in other countries. There are 3 main ISPs that aren't as readily peered together as they are elsewhere. (From what I understand, if you were to run a hosting company inside China for example, you would want - or need - to have deals in place with each ISP).