Terrible performance (10-20 KB/s) with GIF IPv6 tunnel

[bexc]

I recently reactivated my account with Hurricane Electric's tunnelbroker.net. I've created a tunnel, and set it up in opnsense. But I'm seeing terrible performance: pings report around 700 ms latency, and I can only download files over IPv6 at around 10-20 KB/s. Over IPv4 that increases to around 300 KB/s, but when I disable the tunnel v4 downloads jump to over 2 MB/s - and the IPv4 gateway monitoring stops warning about the latency.

I don't expect the same level of performance over a tunnel than I'd get with native IPv6, but I'm guessing there's something wrong locally?

Bex