[tor-relays] tor-relay+polipo+firefox much slower than TBB - why?

[swsnyder at snydernet.net]

I've got an established Tor 0.2.1.30 relay running on a (Linux/x86) machine on my network, and want anonymity while browsing on another machine.  

Sure, I could just download and run the Tor Browser Bundle (Linux/x86_64), but why?  I'm already running Tor, so why not use it for my browsing?  So I run Polipo 1.0.4 on the machine running Tor and just point my browser (Firefox) at Polipo by specifying Polipo as a HTTPS proxy.

It works but it's slow.  After a few weeks I download the current TBB and give it a try, and find that HTTPS browsing is noticeably more responsive than on my tor-relay+polipo+firefox config.  I note the same performance difference over the course of a couple of weeks, so I know it is not just a fluke.

Can someone tell me why that is?

In my configuration both Tor and Polipo are running on a slowish 32-bit machine while the browser is running on a fast 64-bit system.  With the TBB, all the software is running on the faster system.  Still, though, I have to believe that it is the Tor network that would be the bottleneck in both configurations, not the CPUs.

The TBB and my stand-alone Firefox are both of the same vintage, so it's not a matter of one browser just being faster than the other.

Maybe my Tor relay is already pegged at the specified bandwidth limit?  Hardly.  Traffic through the relay averages about %25 of the bandwidth ceiling I set. (That's a topic for another message.)

I would much rather be just another client on my Tor relay than to have a special browser.  What do I have to do to get the TBB performance with a stand-alone tor-relay+polipo config?

Thanks.