I don't think that's quite true because some rendering and downloading happens at the same time - the page starts to render before d/l is complete. Being in the UK I haven't tried an iPhone in person, but from the demos posted on the web, this seems to be a real strength of iPhone Safari: it gives you a pretty good rendering of the page quite quickly and you can be looking at the page as it fills in the missing bits. Is that what you guys (with iPhones) find in practice?
Yes, that is partially true (note: the ARM has only one core, so time spent dealing with incoming data subtracts from time spent rendering, even if it seems simultaneous, except for whatever can be buffered. The iphone probably can buffer more than the older treo as well). But I was trying to simplify. And my experience on blazer/treo is that the pre-page-load rendering is pretty worthless, whereas the iphone renders like a real browser - the page layout doesn't really change, and it just fills in the missing bits (pictures).
The difference seems to be that iphone is designed to multithread, whereas treo/palm just throws the text up as it receives it, then formats and re-draws the page when it is done. I haven't tried WM in awhile, so maybe IE on WM is better than blazer on palm.