Windows Phone 7 slated for a "speed boost"
But how much of a boost? As it turns out, that number is difficult to quantify. The Director of Microsoft's mobile communications, business, Aaron Woodman said "It's not the same percentage of improvement, primarily because what we've done is modify how memory is loaded. So more graphic intense, front-loading applications like games are going to benefit a great deal more from the change in architecture, than a text-driven application,".
Update to include performance improvements