Well typically, modern hardware acceleration uses a 3d capable chip, and pixel operations tend not to be the primary bottleneck nowadays. They can still be a bottleneck, for example if you're drawing lots of blended layers on top of each other, but it's quite different from the old days where you did everything you could to minimise the number of pixels written.

Basic pixel filling by 3d chips is pretty darn fast. So rendering algorithms these days don't try to minimise pixels; they try to minimise lots of other things, including pixels in the overall balance but not so much.

Did I mention that pixels are drawn in parallel with CPU calculations deciding what to send the GPU? So drawing 4 times the pixels does not mean taking 4 times as long for the render, any more.

I say typically. I don't know what the 3d chip and memory is like in the N900. It might be a rubbish one

If it's anything like the Intel Poulsbo debacle, which uses a similar 3d core from the same company, it'll be reasonably good performance (though not latest Nvidia/ATI class), with awful drivers that don't take advantage of it's features despite being closed source. Let's see if Nokia had better luck getting proper drivers for it than regular Linux users have managed (or even Windows users apparently) on Intel Poulsbo chipsets.

From the videos, it looks like the N900 is having no difficulty actually drawing any part of the web page to the screen. That's supported by watching the ball game videos, where the whole 3d scene is running quite smoothly. Much smoother than these scrolling web pages, in fact, despite being a full screen 3d render.

So it looks like the slowness is in calculating what to draw, and with images it's possibly decompressing them on demand into a cache. You can see all that because when the delay finishes and it does finally get round to drawing, it fills in everything rather quickly.

I agree. If there was only one browser I'd look forward to doing that But it turns out there are several alternative browsers already in the pipeline. I'm confident at least one of them will have very smooth scrolling. (And if there isn't, I see an app waiting to be written ) It looks like a microb problem more than a device problem - similar visual artifacts to rendering on Netscape Navigator 4 and IE 4.