The speed at which you download a new copy of the blockchain is more dependent on the # of connections you have with the network. To increase the number of connections to the Bitcoin network and improve Block chain speed open/forward port 8333 to the computer which is running the client.
This will reduce the delay (latency) between the time new transaction/blocks occur and when you learn of them. Having more connections means on average you are closer to any event (the a node submitting a new transaction, or new block solution) and thus learn about it quicker.
Could you clarify what you mean by "client performance"? – D.H. - bitcoin.se – 2011-10-27T19:43:19.790
Added some explanation. I was generally inspired by updating my blockchain on a fast network (compared to my home) and the client not moving as fast as I hoped it would. – ThePiachu – 2011-10-27T19:50:59.683