I'll be interested to have information about the behavior of prefetch hints instructions such as prefetcht0,prefetchnta,prefetchw,... for modern processors such as Sandy Bridge and Ivy Bridge. I ask because there is nothing about it in the optimization guide  apparently. It will be arguably a good thing for developers to know to which cache level data are prefetched with the diverse variants. I'll glad if someone provide a pointer to some detailed explanation.
 Intel® 64 and IA-32 Architectures Optimization Reference Manual, Order Number: 248966-026, April 2012