For not all workloads is Ubuntu 12.10 a dramatic performance improvement over its predecessor, but in some cases the performance is simply maintained but I have yet to see any huge regressions with several different Intel systems I've tested thus far.
Overall, the CompuLab Intense-PC with Intel Core i7 "Ivy Bridge" processor is performing very well with Ubuntu 12.10 and a very nice upgrade already over Ubuntu 12.04 LTS. Most of the performance boosts come from continued optimizations on the open-source Intel graphics driver stack and the move to the GCC 4.7 compiler. Additional performance boosts for Nouveau/Radeon/Intel graphics may come still this cycle when moving to Mesa 8.1/9.0. Expect more Ubuntu 12.10 benchmarks as its release nears in October; there's also forthcoming articles looking at the power consumption and other areas.