Ping times with Tor running

[Kris Linquist]

All,

The answer to this may be "yeah, duh.", just thought I'd ask :).   I've 
got a residential cable connection where I am guaranteed 22mbit down, 
5mbit up.   My Tor relay BandwithRate is 1000 KB  bursting up to 2000 KB.

While Tor is running, incoming and outgoing pings to the nearest hop 
goes from ~15ms to ~300+ms.  This is very obvious when browsing.

Is this expected or do you think it's poor performance by either my ISP 
or cable modem at accepting many connections?

Thanks,
Kris