More memory doesn't make anything go faster. Either you have enough RAM to run your apps or you don't; there isn't any swap space on the iDevices so you never have the "swapping stuff in and out of RAM" issue to slow things down.
--Eric
Sorry to burst your bubble, but you're wrong. Every time you load anything, be it a web page, cover flow album art, music, video - it's pulled from somewhere and into ram. When it's done, it doesn't keep it in memory, it simply couldn't. Data is discarded when no longer immediately needed. If the user has to use it again, it is substantially slower to access it than if it would have just left it in ram. More ram provides the means to keep things in memory longer rather than dumping them. All of this is possible, without the 'swap space' you introduced into the equation.