Intel simply doesn’t want to go over the 4GHz mark, not even with its Sandy Bridge E upcoming high performance CPUs. The six core version clocked at 3.3GHz can natively get to 3.9GHz with turbo overclocking and it looks like the four core version shares the same fate.
The main difference is that the quad core Sandy Bridge E comes with a native clock of quite high 3.6GHz, the fastest we've seen so far and a single core can get to 3.9GHz with a little turbo automatic overclocking assistance.
The quad core Sandy Bridge E has eight tread support, works with 1066 and 1333DDR3 memory and has the expected 130W TDP. Let’s not forget the four way memory support, again a first for Intel's high end products. Sandy Bridge E quad core is still a 32nm product.
We are pretty sure that overclockers will exceed 4GHz with ease and overclockers are indeed the target audience. Naturally, they'll need to reach deep inot their pocket as Enthusiast class CPUs from Intel usually cost an arm and leg.
A very important detail - Sandy Bridge E has no integrated graphics like the rest of Sandy Bridge family.