Core i7-2600K CPU Review

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[nextpage title=”Introduction”]

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.

[nextpage title=”How We Tested”]

During our benchmarking sessions we used the configuration listed below. Between our benchmarking sessions the only variable device was the CPU being tested and the motherboard, which had to be replaced to match the different CPU sockets.

Hardware Configuration

Motherboard (Socket LGA1155): Intel DP67BG (1980 BIOS)
Motherboard (Socket LGA1156): MSI P55-GD85 (1.4 BIOS)
Motherboard (Socket AM3): ASUS Crosshair IV Formula (1304 BIOS)
CPU Cooler: Intel/AMD stock
Memory: 4 GB DDR3-1333, two G.Skill F3-10666CL7T memory modules
Hard Disk Drive: Western Digital Caviar Black 1 TB (WD1001FALS, SATA-300, 7,200 rpm, 32 MB buffer)
Video Card: Radeon HD 6970
Video Monitor: Samsung Syncmaster 305T Plus
Power Supply: Seasonic X-Series 850 W

Operating System Configuration

Windows 7 Ultimate 64-bit
NTFS
Video resolution: 2560×1600 60 Hz

Driver Versions

AMD video driver version: Catalyst 12.0
Intel Inf chipset driver version (Intel DP67BG): 9.2.0.1019
Intel Inf chipset driver version (MSI P55-GD85): 9.1.2.1008
AMD chipset driver version: 3.0.762.0

Software Used

Error Margin

We adopted a 3% error margin. Thus, differences below 3% cannot be considered relevant. In other words, products with a performance difference below 3% should be considered as having similar performance.

[nextpage title=”PCMark Vantage”]

PCMark Vantage simulates the use of real-world applications and gives scores for the following categories:

PCMark
Memories
TV and Movies
Gaming
Music
Communications
Productivity
HDD

For a detailed description of each one of these tests, please download and read the PCMark Vantage Reviewer’s Guide.

You can see the results for each category below. We are not going to compare the results for the Memories and HDD suites.

The Core i7-2600K (3.4 GHz) achieved an overall score on PCMark Vantage 21% higher than the one achieved by the Core i7-875K (2.93 GHz) and 33% higher than the one achieved by the Phenom II X6 1100T (3.3 GHz).

On the TV and Movies benchmark, the Core i7-2600K achieve a score 4% higher than the Core i7-875K’s and 19% higher than the Phenom II X6 1100T’s.

The gaming performance of the Core i7-2600K was 20% higher than the Core i7-875K’s and 39% higher than the Phenom II X6 1100T’s.

On the Music benchmark, the Core i7-2600K achieved a score 7% higher than the Core i7-875K’s and 9% higher than the Phenom II X6 1100T’s.

The Communications score of the Core i7-2600K was 59% higher than the Phenom II X6 1100T’s and 64% higher than the Core i7-875K’s.

The Productivity score of the Core i7-2600K was 4% higher than the Phenom II X6 1100T’s and 8% higher than the Core i7-875K’s.

[nextpage title=”VirtualDub + DivX”]

With VirtualDub we converted a full-length DVD movie to DivX format and saw how long it took for this conversion to be completed. The DivX codec is capable of recognizing and using not only more than one CPU (i.e., more than one core), but also the SSE4 instruction set (feature not available on the reviewed CPUs).

The movie we chose to convert was Star Trek – The Motion Picture: Director’s Cut. We copied the movie to our hard disk drive with no compression, so the final original file on our HDD was 6.79 GB. After compressing it with DivX, the final file was only 767.40 MB, which is quite remarkable.

The results below are given in seconds, so the lower the better.

On DivX encoding the Core i7-2600K (3.4 GHz) was 10% faster than the Core i7-875K (2.93 GHz) and 14% faster than the Phenom II X6 1100T (3.3 GHz).

[nextpage title=”Photoshop CS4″]

The best way to measure performance is by using real programs. The problem, though, is creating a methodology using real software that provides accurate results. For Photoshop CS4, there is a methodology created by the folks at GamingHeaven that is very accurate. Their script applies a series of 15 filters to a sample image, and we wrote down the time taken for each filter to run. At the end, we have the results for each individual filter and we simply added them up to have the total time taken to run the 15 filters from the GamingHeaven batch. The results below are given in seconds, so the lower the number the better.

On Photoshop CS4, the Core i7-2600K (3.4 GHz) was 34% faster than the Core i7-875K (2.93 GHz) and 39% faster than the Phenom II X6 1100T (3.3 GHz).

[nextpage title=”After Effects CS5″]

After Effects is a very well-known program for video post-production that is used to add animation and visual effects in videos. To evaluate the performance of each CPU running this program, we ran a workload consisting of several compositions that applied several filters and effects to a variety of input file types such as PSD (Photoshop), AI (Illustrator), EPS, and TIF. After each filter was applied, the composition was rendered to an uncompressed AVI file with the same resolution as the input files. The results below are the time each CPU took to finish the whole batch, given in seconds, so the lower the number the better.

On After Effects CS5, the Core i7-2600K (3.4 GHz) was 18% faster than the Core i7-875K (2.93 GHz) and 37% faster than the Phenom II X6 1100T (3.3 GHz).

[nextpage title=”WinZip”]

We used WinZip not only to measure compression time, but also decryption time. We measured the time each CPU took to decompress and decrypt 200 JPEG images, 125 of them at 10 megapixels and 75 of them at six megapixels. The total size of all the photos was around 830 MB. The results below are given in seconds, so the lower the number the better.

Decompressing and decrypting files, the Core i7-2600K (3.4 GHz) was 19% faster than the Core i7-875K (2.93 GHz) and 33% faster than the Phenom II X6 1100T (3.3 GHz).

[nextpage title=”iTunes”]

We used iTunes to convert an uncompressed .wav file into a high-quality (160 Kbps) M
P3 file, and checked how many seconds each CPU took to perform this operation. Therefore, the results below are given in seconds, so the lower the number the better.

On MP3 file conversion, the Core i7-2600 K (3.4 GHz) was 12% faster than the Phenom II X6 1100T (3.3 GHz) and the Core i7-875K (2.93 GHz), which achieved the same performance.

[nextpage title=”Cinebench 11.5″]

Cinebench 11.5 is based on the 3D software, Cinema 4d. It is very useful to measure the performance gain given by having more than one CPU installed on the system when rendering heavy 3D images. Rendering is one area in which having more than one CPU helps considerably, because usually, rendering software recognizes several CPUs. (Cinebench, for instance, can use up to 16 CPUs.)

Since we were interested in measuring the rendering performance, we ran the test called “Rendering x CPUs,” which renders a “heavy” sample image using all available CPUs (or cores – either real or virtual, as on CPUs with Hyper-Threading technology, each core is recognized as two cores by the operating system) to speed up the process.

On Cinebench, the Core i7-2600K (3.4 GHz) was 17% faster than the Phenom II X6 1100T (3.3 GHz) and 25% faster than the Core i7-875K (2.93 GHz). This is an impressive result, since the Phenom II X6 1100T is a six-core CPU, while the Core i7-2600K is a quad-core CPU with Hyper-Threading technology, and usually CPUs with more “real” cores are the ones that achieve the best results on Cinebench.

[nextpage title=”Call of Duty 4″]

Call of Duty 4 is a DirectX 9 game implementing high-dynamic range (HDR) and its own physics engine. We ran this game at 1920×1200 with all image quality settings at their minimum values (no anti-aliasing and no anisotropic filtering). We used the game internal benchmarking feature, running a demo provided by nVidia called wetwork. We are putting this demo for downloading here if you want to run your own benchmarking. The game was updated to version 1.7. We ran this test five times, discarding the lowest and the highest scores. The results below are an arithmetic average of the three remaining values, given in frames per second (FPS).

On Call of Duty 4, the Core i7-2600K (3.4 GHz) was 9% faster than the Core i7-875K (2.93 GHz) and 12% faster than the Phenom II X6 1100T (3.3 GHz). It is important to understand that we lowered the image quality settings to their minimum values in order to measure the CPU performance; by increasing image quality settings you start to measure the performance of the video card, not the CPU, and under this scenario all CPUs will get similar performance on this game. Since users buying a high-end CPU to play games will probably buy a high-end video card and max out image quality settings, the gaming performance will be set by the video card, and not by the CPU.

[nextpage title=”StarCraft II: Wings of Liberty”]

StarCraft II: Wings of Liberty is a very popular DirectX 9 game that was released in 2010. Though this game uses an old version of DirectX, the number of textures that can be represented on one screen can push most of the top-end graphics cards to their limits (especially when the graphics settings are set at “Ultra”). StarCraft II: Wings of Liberty uses its own physics engine that is bound to the CPU and thus does not benefit from PhysX.

We tested this game at 1920×1200. The quality of the game was set to the “low” preset, disabling both anti-aliasing and anisotropic filtering. We then used FRAPS to collect the frame rate of a replay on the “Unit Testing” custom map. We used a battle between very large armies to stress the video cards.

On StarCraft II, the Core i7-2600K (3.4 GHz) was 11% faster than the Core i7-875K (2.93 GHz) and 16% faster than the Phenom II X6 1100T (3.3 GHz). It is important to understand that we lowered the image quality settings to their minimum values in order to measure the CPU performance; by increasing image quality settings you start to measure the performance of the video card, not the CPU, and under this scenario all CPUs will get similar performance on this game. Since users buying a high-end CPU to play games will probably buy a high-end video card and max out image quality settings, the gaming performance will be set by the video card, and not by the CPU.

[nextpage title=”Far Cry 2″]

Far Cry 2 is based on an entire new game engine called Dunia, which is based on DirectX 10 when played under Windows 7 or Windows Vista with a DirectX 10-compatible video card. We used the benchmarking utility that comes with this game, setting video resolution to 1920×1200, overall image quality to “high” (this is the lowest possible setting if you want to run this game at DirectX 10), setting all “Performance” options to “low,” disabling both anti-aliasing and anisotropic filtering, and running the demo “Ranch Long.” The results below are expressed in frames per second.

On Far Cry 2, the Core i7-2600K (3.4 GHz) was 12% faster than the Core i7-875K (2.93 GHz) and 15% faster than the Phenom II X6 1100T (3.3 GHz). It is important to understand that we lowered the image quality settings to their minimum values in order to measure the CPU performance; by increasing image quality settings you start to measure the performance of the video card, not the CPU, and under this scenario all CPUs will get similar performance on this game. Since users buying a high-end CPU to play games will probably buy a high-end video card and max out image quality settings, the gaming performance will be set by the video card, and not by the CPU.

[nextpage title=”Lost Planet 2″]

Lost Planet 2 is a game that uses a lot of DirectX 11 features, like tessellation (to round out the edges of polygonal models), displacement maps (added to the tessellated mesh to add fine grain details), DirectCompute soft body simulation (to introduce more realism in the “boss” monsters), and DirectCompute wave simulation (to introduce more realism in the physics calculations in water surfaces; when you move or when gunshots and explosions hit the water, it moves accordingly). We reviewed the CPUs using Lost Planet 2 internal benchmarking features, choosing the “Benchmark A” (we know that “Benchmark B” is the one recommended for reviewing video cards, however, at least with us, results were inconsistent). We ran th
is game at 1920×1200 with graphics set at “low,” with no anti-aliasing and no anisotropic filtering. The results below are the number of frames per second generated by each system.

On Lost Planet 2, the Core i7-2600K (3.4 GHz) was 9% faster than the Core i7-875K (2.93 GHz) and 13% faster than the Phenom II X6 1100T (3.3 GHz). It is important to understand that we lowered the image quality settings to their minimum values in order to measure the CPU performance; by increasing image quality settings you start to measure the performance of the video card, not the CPU, and under this scenario all CPUs will get similar performance on this game. Since users buying a high-end CPU to play games will probably buy a high-end video card and max out image quality settings, the gaming performance will be set by the video card, and not by the CPU.

[nextpage title=”3DMark 11 Professional”]

3DMark 11 Professional measures Shader 5.0 (i.e., DirectX 11) performance. We ran this program at 1920×1200 using the “Performance” profile. This program provides three different scores: graphics, physics and combined.

All CPUs achieved comparable graphics scores. This was expected, since this number measures exclusively the video card performance, not taking the CPU into account.

The physics score measures exclusively the physics performance of the system, in our case the CPU performance, as the video card was always the same. Here the Core i7-2600K (3.4 GHz) was 20% faster than the Phenom II X6 1100T (3.3 GHz) and 53% faster than the Core i7-875K (2.93 GHz).

The combined score shows a balance between the graphics and the physics performance achieved by each system being tested. Here the three CPUs achieved the same performance level.

[nextpage title=”Overclocking”]

Like the Core i5-2500K, which is also based on the “Sandy Bridge” architecture, the new Core i7-2600K (3.4 GHz) proved to be an outstanding CPU for overclocking.

The Core i7-2600K gets internal 3.4 GHz by multiplying its 100 MHz base clock 34 times.

To overclock the Core i7-2600K, we used an MSI P67A-GD65 motherboard (1.0 BIOS). Increasing the CPU voltage to 1.45 V, we were able to increase the CPU clock multiplier up to x48, making the CPU to run stable at 4.8 GHz internally. Increasing the CPU voltage a little bit more to 1.50 V we were able to push the clock multiplier one notch. At x49, our CPU was running internally at 4.9 GHz stable, a 44.1% increase in the CPU internal clock rate. Outstanding.

It is very important to remember that we got an engineering sample from Intel, which may have a higher overclocking capability than the final product that will arrive on the market.

We didn’t play a lot with all overclocking options, and you may achieve even better results.

[nextpage title=”Conclusions”]

The Core i7-2600K (3.4 GHz) proved to be an impressive product for the user looking for a high-end CPU. Available for the same price as the Core i7-875K (2.93 GHz), the new Core i7-2600K (3.4 GHz) was faster in all programs we ran (except on 3DMark 11, where the performance being measured was actually the video card’s, not the CPU’s), making it a no-brainer if you were contemplating buying the Core i7-875K.

The reviewed CPU doesn’t have a direct competitor, since the most expensive CPU from AMD – the Phenom II X6 1100T (3.3 GHz) – costs USD 60 less. In any case, the Core i7-2600K was faster than the Phenom II X6 1100T in all programs we ran (again, except on 3DMark 11).

Like the Core i5-2500K, one of the highlights of the new Core i7-2600K is its outstanding overclocking capability. We were able to put it to run at 4.9 GHz, an impressive 44.1% increase in the CPU’s internal clock rate.

It is important to understand that for most users the Core i5-2500K provides a better cost/benefit ratio than the Core i7-2600K, and you still get an unprecedented overclocking capability. Gaming performance (if you increase image quality settings) is dictated mainly by the video card, not by the CPU (unless you use a low-end CPU), and therefore you can save some money buying the new Core i5-2500K instead of the Core i7-2600K and invest the difference in a more expensive video card.

However, if you are a professional user working with video and photo editing, 3D rendering, and other applications that really need more processing power, you will surely benefit from the new Core i7-2600K and its very attractive price for this kind of use.

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