Introduction
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Intel launched this month their new CPUs based on the “Sandy Bridge” architecture. Let’s check the performance of the new Core i7-2600K (3.4 GHz) and compare it to the CPU it came to replace, the Core i7-875K (2.93 GHz), and to the most expensive CPU from AMD, the Phenom II X6 1100T (3.3 GHz).
For a detailed explanation of what is new in the Sandy Bridge architecture, please read our Inside the Intel Sandy Bridge Microarchitecture tutorial.
The new Core i7-2600K (3.4 GHz) is a quad-core CPU, coming in two flavors: with its clock multiplier unlocked (“K,” being the equivalent to the “Extreme Edition” CPUs Intel used to carry and to the “Black Edition” CPUs from AMD), giving you an extra way to overclock the CPU, and the standard model with a locked clock multiplier. The “K” model can be found today costing USD 330, while the standard model can be found for USD 300.
The Core i7-2600K comes with Hyper-Threading technology, meaning that the operating system recognizes eight CPUs, two per CPU core. Of course these extra “cores” are simulated.
We decided to compare the new Core i7-2600K (3.4 GHz) with the Core i7-875K (2.93 GHz), since both carry similar price tags.
The truth is that the new Core i7-2600K (3.4 GHz) has no direct competition. The most expensive CPU AMD currently has is the Phenom II X6 1100T (3.3 GHz), at USD 270, which is a six-core CPU. Therefore, throughout our review we will consider it as the Core i7-2600K’s main competitor, since no other CPU fits this spot.
| CPU | Cores | HT | IGP | Internal Clock | Turbo Clock | Base Clock | Core | Technology | TDP | Socket | Price |
| Core i7-2600K | 4 | Yes | Yes | 3.40 GHz | 3.8 GHz | 100 MHz | Sandy Bridge | 32 nm | 95 W | 1155 | USD 330 |
| Core i7-875K | 4 | Yes | No | 2.93 GHz | 3.6 GHz | 133 MHz | Lynnfield | 45 nm | 95 W | 1156 | USD 340 |
| Phenom II X6 1100T | 6 | No | No | 3.3 GHz | 3.7 GHz | 200 MHz | Thuban | 45 nm | 125 W | AM3 | USD 270 |
TDP stands for Thermal Design Power which advises the user of the maximum amount of heat the CPU can dissipate. The CPU cooler must be capable of dissipating at least this amount of heat.
Prices were researched at Newegg.com on the day we published this review.
| CPU | L1 Cache | L2 Cache | L3 Cache | Memory Support | Memory Channels |
| Core i7-2600K | 32 KB + 32 KB per core | 256 KB per core | 8 MB total | DDR3 up to 1333 MHz | Two |
| Core i7-875K | 32 KB + 32 KB per core | 256 KB per core | 8 MB total | DDR3 up to 1333 MHz | Two |
| Phenom II X6 1100T | 64 KB + 64 KB per core | 512 KB per core | 6 MB total | DDR3 up to 1333 MHz | Two |
While all CPUs listed above have an integrated memory controller, only the new Core i7-2600K has an integrated graphics processor (IGP). Both the Core i7-2600K and the Core i7-875K have an integrated PCI Express 2.0 controller, handling 16 PCI Express lanes, allowing those CPUs to drive one PCI Express slot at x16 or two PCI Express slots at x8.
AMD CPUs talk to the external world (i.e. the chipset) thru a bus called HyperTransport. For a detailed explanation how this bus works, please read our The HyperTransport Bus Used by AMD Processors tutorial.
Socket LGA1156 and 1155 CPUs use the DMI (Digital Media Interface) bus to talk to the chipset, which is the interface previously used to make the connection between the north bridge and the south bridge chips on Intel chipsets.