The problem with the latency on Tor is not the bandwidth, (Tor can download a 1mb file quite quickly), it's the ping. This is an aspect of the onion routing mod

The problem with the latency on Tor is not the bandwidth, (Tor can download a 1mb file quite quickly), it's the ping. This is an aspect of the onion routing model, not the fact that volunteers run nodes. There are proposals to switch from HTTP to a faster protocol from the exit to the user. It's expected this would result in an observable latency improvement for web browsing.