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.