Not that it has an extra 64mb, it has the memory, unlike the X-fi XtremeMusic and X-fi Platinum. There are two reasons why there is not an actual FPS boost.
1. It is not meant to boost FPS, it is meant to cache up to 128 hardware sound sources and higher quality sounds.
2. The only games that currently takes advantage of the RAM is BF2, and FEAR does take advantage of the X-fi, but not the new memory. Most games that will be coming out now will take advantage of it. When you get a sound card for gaming, you want to look that it supports the latest version of EAX (5.0), which all the X-fi cards do, and you want to see how many sounds it can process in hardware, which all the X-fi cards can do 128, which is currently the best, and the features it has, like the added RAM, etc...
so, umm, err yeah