Ubuntu 12.10 Prepares To Improve Linux Performance
For some disk workloads there may be performance improvements for your HDD or SSD when using the EXT4 file-system on the more recent kernel. EXT4 will remain the default for Ubuntu 12.10 and they will not be switching to Btrfs at this time.
For the computationally intensive workloads, for several different processor architectures there should be performance improvements when built by the GCC 4.7 compiler. GCC 4.7 has improved support for Sandy Bridge, proper Ivy Bridge support, and even early support for Intel's 2013 Haswell platform. There are improvements on the AMD side too.