Now with 2.2 (froyo) it can run up to 4 times faster.
The 4x increase refers to a JIT compiler, it'll give a 4x speed increase in very, very specific circumstances. It has to be very CPU heavy code, which is repeatedly run, like a program which you give a photo and it applies a filter for example. The compilation requires a bit of time and memory, so in some circumstances it's actually slower. It's not a win/win, for the vast majority of things it'll make no difference.
The Snapdragon processor has their own crappy GPU, which is fill rate bound, which means, although it's fast at figuring things out internally, it's actually too slow to draw it's big screen at a decent speed. With a 3.7" screen this cap was about 26 frames per second, if the new one is a higher res this will be even worse.
The Hummingbird phones, new Nvidia ones, or iPhones A8s are far more speedy and capable of a much better frame rate. All with proper 3d hardware, faster and more up to date than the likes of a PSP. The reason everything runs smooth on the Desire is because it's all made for the Desire, as it's selling bucket loads.
have you actually tired one?
Yes, and I'm developing for it 🙂 It'd be nice to release something crazy and blow everyones socks off, like id and Epic recently did for the iPhone. Sadly the HTC phones gimp this potential a bit.