Nehalem
From Mac Guides
Nehalem is a processor microarchitecture being developed by Intel and is the successor to Penryn. Nehalem uses the 45nm manufacturing methods from Penryn and applies it to the new microarchitecture. Transition to 32nm is expected by 2010. It will be introduced over the period from late 2008 to Q3 2009.
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Nomenclature
The high-end desktop variant of Nehalem is called Core i7. Other variants will have different names.
Features
Nehalem will be Intel's second architecture change of such magnitude, the first being Pentium Pro in 1995. Nehalem is highly scalable with diversified multi-component functioning. Some of the notable new features in the architecture are:
- 45 nm process, later 32 nm.
- 2, 4, 6, or 8 core processing.
- Integrated memory controller supporting DDR3 SDRAM and between 1 and 4 memory channels.
- Point-to-Point processor interconnect, the Intel QuickPath Interconnect, replacing the legacy front side bus (FSB) for some variants of Nehalem.
- New simultaneous multithreading, which enables two threads per core. Intel now calls this technology as MTT rather than SMT as in the Conroe and Penryn architectures.
- 32 KB L1 inst cache and 32 KB L1 data cache per core, 256 KB L2 cache per core and 2-3 MB L3 cache per core shared by all cores.
- 30% lower power usage for the same performance.
Intel QuickPath Interconnect
The Intel QuickPath Interconnect or simply QuickPath (the official legal name for Common System Interface or CSI) is a point-to-point processor interconnect being developed by Intel, as a competitor to HyperTransport. QuickPath technology also includes an integrated memory controller. It will replace the Front Side Bus (FSB) for Xeon and Itanium platforms. It is expected to be released in late 2008 and will first be used by Intel's Nehalem and Tukwila processors.
Nehalem is expected to attain a 20-bit wide 25.6 GB/s link which is exactly double the maximum theoretical bandwidth offered by Intel's current architectural offering as FSB in Penryn.
