> I know this is 100% speculation, so nobody quote me on that. But let's > assume that it is. What will give better overall performance in OS X? I > never use OS 9 or classic, so please don't consider that. Will having > two > 800 MHz processors have more effect than one that is 50% faster? > > Thanks for your theories & observations. I'd go for a single any time. Now there are exceptions, like rendering software, certain photoshop operations etc that really use the multiple processors, so if you are using those most of the time, go for a dual. And there are also stories of burned dc/dc boards with duals :)