Yesterday's keynote came with the somewhat obvious news that the iPhone 5s was way faster than the iPhone 5. The number Apple threw out was that it had the graphical performance that exceeds the original iPhone by "up to 56x" which, admittedly, is fairly hard to visualize. Thankfully, it'd seem that someone during one of the hands on sessions yesterday installed GFXBench [Free] and ran the Egypt HD 2.5 tests. Again, it's not much of a surprise, but the iPhone 5S is getting just under double the framerate of the iPhone 5 in offscreen tests. While the onscreen results aren't as impressive, it still shows a nice boost.
Now, these results come with the massive caveat that GFXBench in its current implementation doesn't even know what the iPhone 5s is, as it is neither optimized for the A7 architecture nor does it take advantage of the iPhone 5s OpenGL ES 3.0 support. Regardless, it seems safe to assume that these results seem like a good starting point for what we should expect for the differences in performance in existing iOS games that aren't updated or optimized for the new device.