Before we start I wish to link you to one of our two previous SB-E related reviews for more info on the architecture. You can quickly read up here

As mentioned in the introduction, this Quad core CPU is launched at an affordable price of 290 euros. Placing it in the same price category as Intels 2600K CPU and a tad more expensive then AMD's FX-8150 (retailing around 230 euros) But the SnB-e platform has got a lot going for it, compared to the socket 1366 and 1155, we list some of the main features :

up to 40 PCIe 2.0 lanes (PCIe 3.0 compatible) ideal for multi GPU solutions

Quad channel ram action up to 51.2Gb/s bandwith

Massive ram support up to 64Gb

Turbo Boost 2.0 (also on S1155 CPU's)

Our i7-3820 runs at 3600Mhz, which is 300-400Mhz more than both hexacore models. The Turbo boost was initially mentioned, even on the Intel slides at 3900Mhz. But we never could get 3900Mhz done on the Intel Siler board. The board's latest bios (0424) also mentioned max Turbo multiplier at 38X. Weird as on the ASUS X79 Sabretooth we regularly saw 3900Mhz popping up in the CPU-Z tab. Either there is a bug in the Siler bios. Or Intel has stepped down the max Turbo frequency 100Mhz to max 3800Mhz and other manufacturers still need to adjust the Turbo ratio in their biosses. Looking at the Intel i7-3820 tech sheet, there's again 3800Mhz mentioned ( link here ) After mailing Intel bout my findings, I was linked to the former mentioned tech sheet. There's no 3900mhz Turbo on the i7-3820 according my Intel contacts.

The Level 3 cache is capped at 10Mb, which procentual is the same value as the high end i7-3960X model. The Die Size is logically smaller, as the two other models, 294mm² versus 435mm². Transistor count totals at 1.27 Billion versus 2.27 Billion for the 6 cores. Most important is that the multiplier is no longer unlocked, but partially locked. At first we guessed it would have been similar to the max turbo ratio multiplier. Then there were more speculations of a free selectable multiplier up to 45X. Our ES sample wouldn't go any higher then 43X on several motherboards. Not bad taking into consideration that we can opt to use the 1.25 Bclock divider, topping out at a very nice 5.37Ghz. So there's more than plenty of headroom for some extra cost free performance.