Thanks for your interest in testing Intel IPP 7.0 Beta on the Sandy Bridge platform. I'd recommend this article http://software.intel.com/en-us/articles/intel-ipp-functions-optimized-for-intel-avx-intel-advanced-... which may addresse some of your questions.
Also, the current IPP 7.0 beta only manually supports theAVX code ( see this article) if the architecture supports it, however in upcoming IPP 7.0 beta release updates, the AVX code will be automaically used. So please check out our release updates periodcially. If you see any performance degradation in the latest 7.0, please provide us more details on the specific APIs or test case , we will look into it.
See this article.
The current beta requires that you still "force" the dispatcher to identify an AVX processor. In the final release of the product the dispatcher will automatically identify AVX hardware and this extra init step won't be required.
I have not checked, but I doubt that the IPP samples include that extra init call to make AVX work, especially given that this is a temporary situation and very, very few people actually have access to AVX hardware (it is currently only available as an evaluation platform).
But in general, as Paul said, auto dispatching to AVX will be enabled in IPP 7.0 final release.