The new thing about the second Core generation codenamed Sandy Bridge is that only the top branded CPUs will have feature hyperthreading.
Hypertreds don’t do that much but they do show you that you have „eight cores“ in Windows task manager and you will only see eight threads with top Core i7 CPUs.
Core i5 CPUs will be a native quad-core CPUs but they won’t support hyperthreading. This will be exclusively reserved for Core i7 2000 series parts. Core i3 native dual-cores will only support two treads which is step down from current Core i3 CPUs that feature two cores and support four threads.
The trend of lack of Turbo support in Core i3 generation will continue with new Sandy Bridge based Core i3 2000 series CPUs.
This is the branding and performance distinction that Intel wants to make clearer in 2011 as most people got confused with Core i branding, as Core i5 and Core i7 were overlapping in many performance and feature characteristics. Now the distinction should be more clear, but it looks to us that in most cases you will get less for the same money.