Intel Core i5 Architecture
The Intel Core i5 750 is based of Intel's Nehalem architecture. Nehalem is Intel's most current architecture as of late 2010 - it replaced the Core 2 Duo and Quad and will itself be replaced by new Sandy Bridge processors in 2011.
The cores in a Nehalem processor are still a branch of the Pentium Pro tree which has been in existence for over a decade, but there are many differences between the older Core 2 Duo processors and the new Nehalem models. One major new feature - Turbo Boost - was introduced. This feature makes it possible for the Core i5 750 to dynamically alters its clock speed whenever the processor is operating below its thermal limit. Although the base clock speed is 2.66 GHz, a Core i5 750 will often be running at speeds up to 3.2 GHz. Obviously, this provides a serious boost to performance.
Another major feature in the Nehalem architecture is hyper-threading. Hyper-threading improves multi-threaded performance by making it possible for each processor core to schedule two threads at once. Because of this feature every core in a Core i5 750 appears as two cores in Windows - so the Core i5 750 appears to be an eight-core processor when viewed in Windows Task Manager. Hyper-threading isn't a new feature, however. The Pentium 4 architecture also had this feature, but Intel dropped it for the Core and Core 2 architectures.
Nehalem was also the first processor from Intel to integrate the memory controller. The Core i5 750 also has an integrated PCIe 2.0 controller. The result of these particular differences is not substantial in terms of performance, but the change does further improve the power efficiency of the Nehalem architecture. The Core i5 750, like all Nehalem processors, provides great performance without consuming gobs of power.