OK, they are not the most objective source, but graphics processor manufacturer nVidia does make a pretty convincing argument for spending more money on a computer’s graphics card and less on the main processor—in certain conditions.

I met with them last week to hear their case, and today they launched a new site to help people calculate how much polygon muscle they need. The gist: Often you can get better performance for the same amount of money if you spend more on the graphics processing unit (GPU) and less on the central processing unit (CPU). Now, the GPU is inconsequential if all you do are tasks like e-mailing, light Web surfing, and preparing documents in Word and Excel. But in some cases, the GPU makes a big difference. 3D video games are a given, but intensive graphics are creeping into many other applications. Google Earth, for example, now provides 3D views of urban landscapes, and my poor iMac nearly overheated trying to render a view of downtown Manhattan. A little less power-intensive, but maybe even more fun, is PicLens—a web browser plug-in that lets you navigate photo sites like Flickr or Google’s image search in 3D, similar to how you flip though album covers in iTunes.