By far the biggest win is probably replacing dozens of TCP sockets with one streaming connection for loading content. After that, shrinking images, and maybe o

By far the biggest win is probably replacing dozens of TCP sockets with one streaming connection for loading content. After that, shrinking images, and maybe offloading some CPU (JS compilation, layout). The "browser cache" story is less clear to me. Caching is an imperfect science. Some resources can't be cached, or the server doesn't it make it clear they can. On the other hand, the most "popular" resources may already be served by CDNs with very low latency compared to your wireless connection. Plus, does the iPhone really suffer from a shortage of cache? A shortage of RAM, sure, which is why tabs are frequently evicted, but how much cache do you really need? Safari on my desktop only has 180 MB in cache, which my iPhone could easily store.