As we've seen from the spec, the X1950 XTX isn't a next-generation product, merely a speed bump over the X1900 XTX. Since both of these GPUs share the same speed, there will be times where you won't see a huge performance increase, if any. However, the more memory-intensive games you're running, the bigger the performance increase.
The X1950 XTX really comes into its own is when you enable full-screen anti-aliasing (FSAA) and anisotropic filtering (AF) at higher resolutions, something that hasn't always been possible with older cards without experiencing a slowdown. There is still a performance penalty but you now need to push past a screen resolution of 1,600 x 1,200 before this will really be noticeable in most games.
As we used beta drivers, there is likely to be performance improvements with the retail drivers, which launched too late for us to use. Nonetheless, the numbers are at least in the ballpark of what you would expect from a top of the range card like this. If you already own an X1900 XTX there won't be any real reason to upgrade, apart from the quiet cooler. Even then, you'd be better off buying an after-market cooler for your current card.