Sandy Bridge-E: What’s New?
The idea behind LGA 2011 platform and compatible processors is to combine the best of both worlds: second-generation Core microarchitecture and LGA 1366 enthusiast platform. The result is a new Core i7 manufactured with the latest 32 nm process and based on
Since Intel used modular approach to their processor design, one of the possibilities for them could be adding two more cores to the Sandy Bridge processors and updating their memory and PCI Express bus controllers. But at the same time the developers decided to take into consideration the needs of the server market clients and come up with a unified product that could successfully be used in high-performance desktops as well as servers. Therefore, the new Sandy Bridge-E boasts a bit more new and unusual features than we would expect in the beginning. For example, these processors do not have an integrated graphics core, but instead they have a QPI bus controller used to tie together processors in multi-socket systems. But the most amazing thing is that Sandy Bridge-E in reality has not six but eight computational cores!
Sandy Bridge-E semiconductor die
This eight-core die manufactured with 32 nm process consists of 2.27 billion transistors and measures 435 mm2 in size. In other words, Sandy Bridge-E die is more than twice as complex and large as the die in regular quad-core Sandy Bridge CPUs.
Unfortunately, the full functionality of the Sandy Bridge-E processors will be available only in servers where they will be offered in the beginning of next year under Xeon E5 brand name. As for us, desktop users, we will be dealing with a slightly simpler incarnation – 3000-series Core i7 processors. This CPU series will include four and six-core CPUs with “blocked” additional cores, smaller L3 cache and disabled QPI bus. However, we can’t really blame the new Core i7 processors for anything: they are superior to any other existing desktop processors in almost all formal specifications.
To back up this statement we put together a table with all major features of the top Core i7 processors from different generations designed for different platforms.
There are only two instances where the new Core i7 reveal their weaknesses. First, we do not see any progress in clock frequency, because Sandy Bridge-E semiconductor die is significantly larger than the die of the previous-generation processors. Moreover, we even observe certain regress: the base clock of the top new CPU models is lower than that of Core i7-2700K and Core i7-990X. However, Intel uses their Turbo Boost 2.0 technology to partially make up for this drawback. Desktop Sandy Bridge-E processors may accelerate to 3.8-3.9 GHz and this frequency is no longer below the maximum reachable by top LGA 1155 and LGA 1366 processors.
The second downside of the new
However, new Core i7 processors have much more advantages. Among them are such things as progressive microarchitecture that supports all contemporary instructions including SSE4.2 and AVX, up to six processor cores with Hyper-Threading support, an advanced PCI Express bus controller supporting up to 40 PCIe lanes that can be configured for multiple usage models right in the processor, large L3 cache reaching 15 MB in size.