Phenom II X4 840 CPU Review

The new Phenom II X4 840 (3.2 GHz), is a very affordable quad-core CPU. In fact, it is the best CPU on the USD 100 price range. Let’s see why.

At USD 100, the main competitor to the Phenom II X4 840 (3.2 GHz) is the Pentium E6800 (3.33 GHz), a dual-core CPU using the socket LGA775. The cheapest Core i3, the 530, is quoted at USD 120, thus being 20% more expensive than the Phenom II X4 840 and not being its direct competitor. We are going to compare the new Phenom II X4 840 (3.2 GHz) to the Athlon II X4 635 (2.9 GHz), since both are in the same price range.

In the tables below you can see a brief comparison between the CPUs we included in our review. AMD CPUs do not support SSE4 instructions (they have a proprietary instruction set called SSE4a, which is not the same thing as SSE4).

CPU	Cores	Internal Clock	Base Clock	Core
Phenom II X4 840	4	3.2 GHz	200 MHz	Propus
Athlon II X4 635	4	2.9 GHz	200 MHz	Propus
Pentium E6800	2	3.33 GHz	266 MHz	Wolfdale

CPU	Technology	TDP	Socket	Price
Phenom II X4 840	45 nm	95 W	AM3	USD 100
Athlon II X4 635	45 nm	95 W	AM3	USD 98
Pentium E6800	45 nm	65 W	775	USD 100

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.

CPU	L1 Cache	L2 Cache
Phenom II X4 840	64 KB + 64 KB per core	512 KB per core
Athlon II X4 635	64 KB + 64 KB per core	512 KB per core
Pentium E6800	32 KB + 32 KB per core	2 MB total

CPU	L3 Cache	Memory Support	Memory Channels
Phenom II X4 840	None	Up to DDR3-1333	Two
Athlon II X4 635	None	Up to DDR3-1333	Two
Pentium E6800	None	*	*

(*) The memory controller is not integrated in the CPU and thus these parameters depend on the chipset/motherboard. In our case, the motherboard we used supported only DDR2 memory up to DDR2-800 (officially), under dual-channel architecture.

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. The Pentium E6800 talks to the external world through a front-side bus (FSB) running at 266 MHz (1,066 MHz QDR).

In our tests, we used motherboards with integrated video. We used a motherboard based on the AMD 880G chipset with the AMD processors, and a motherboard based on the Intel G45 chipset with the Intel processors. We wanted to keep both systems around the same price range, and this is why we didn’t use a motherboard with a “stronger” chipset (e.g., AMD 890GX) with the AMD CPUs. In our gaming tests, we measured the performance of the integrated video and also installed an entry-level DirectX 11 video card (GeForce GT 430), so you will be able to compare the performance of the CPUs when a “real” video card is installed.

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 AM3): ASRock 880GXH/USB3 (1.20 BIOS)
Motherboard (Socket LGA775): Intel DG45ID (0131 BIOS)
CPU Cooler: Intel/AMD stock
Memory (Socket AM3): 4 GB DDR3-1333, two G.Skill F3-10666CL7T memory modules
Memory (Socket LGA775): 4 GB DDR2-800, four Crucial CT12864AA800.M8FE memory modules
Hard Disk Drive: Western Digital Caviar Black 1 TB (WD1001FALS, SATA-300, 7,200 rpm, 32 MB buffer)
Video Card: GeForce GT 430 (used on some tests only)
Video Monitor: Samsung Syncmaster 932BW
Power Supply: OCZ StealthXStream 400 W

Operating System Configuration

Windows 7 Ultimate 64-bit
NTFS
Video resolution: 1440×90 60 Hz

Driver Versions

NVIDIA video driver version: 266.58
Intel video driver version: 15.17.10.2189
AMD video driver version: 8.71
Intel Inf chipset driver version: 9.1.2.1008
AMD chipset driver version: 8.631

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.

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 Phenom II X4 840 (3.2 GHz) achieved the highest PCMark Vantage score, which was 12% higher than the one achieved by the Athlon II X4 635 (2.9 GHz) and 16% higher than the one achieved by the Pentium E6800 (3.33 GHz).

The TV and Movies score of the Phenom II X4 840 (3.2 GHz) was 7% higher than the one achieved by the Athlon II X4 635 (2.9 GHz) and 23% higher than the one achieved by the Pentium E6800 (3.33 GHz).

On the Gaming benchmark, the Phenom II X4 840 (3.2 GHz) got a tiny 4% vantage over the Athlon II X4 635 (2.9 GHz), but achieved a score 20% higher than the Pentium E6800’s.

On Music, the Pentium E6800 (3.33 GHz) was actually the fastest CPU, with a score 5% higher than the Phenom II X4 840’s and 8% higher than the Athlon II 635’s.

On Communications, the Pentium E6800 (3.33 GHz) was the fastest CPU once more, with a score 14% higher than the Athlon II X4 635’s and 15% higher than the Phenom II X4 840’s.

And on Productivity, the Phenom II X4 840 (3.2 GHz) achieve a score 6% higher than Athlon II X4 635’s and 39% higher than Pentium E6800’s.

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 Phenom II X4 840 (3.2 GHz) was 5% faster than the Athlon II X4 635 (2.9 GHz) and 21% faster than the Pentium E6800 (3.33 GHz).

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 DivX encoding the Phenom II X4 840 (3.2 GHz) was 5% faster than the Athlon II X4 635 (2.9 GHz) and 21% faster than the Pentium E6800 (3.33 GHz).

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 Phenom II X4 840 (3.2 GHz) was 8% faster than the Athlon II X4 635 (2.9 GHz) and 22% faster than the Pentium E6800 (3.33 GHz).

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 Phenom II X4 840 (3.2 GHz) was 8% faster than the Athlon II X4 635 (2.9 GHz) and 18% faster than the Pentium E6800 (3.33 GHz).

We used iTunes to convert an uncompressed .wav file into a high-quality (160 Kbps) MP3 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.

The Phenom II X4 840 (3.2 GHz) was the fastest CPU for MP3 converting, being 9% faster than the Athlon II X4 635 (2.9 GHz) and 15% faster than the Pentium
E6800 (3.33 GHz).

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 Phenom II X4 840 (3.2 GHz) achieved the highest score, 10% higher than the one achieved by the Athlon II X4 635 (2.9 GHz) and 89% higher than the one achieved by the Pentium E6800 (3.33 GHz).

Call of Duty 4 is a DirectX 9 game implementing high-dynamic range (HDR) and its own physics engine. We ran this game at 1440×900 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).

We ran this game twice with each CPU. First, we used the CPU or chipset integrated graphics. Then we added a GeForce GT 430 video card, which is an entry-level DirectX 11 video card. We used an entry-level video card because we wanted to see the impact each CPU had in the performance achieved (when using high-end video cards, the CPU role in gaming performance is reduced).

Let’s compare the results using the chipset integrated graphics first. On this game the graphics processor of the Intel G45 chipset was faster than the one from the AMD 880G chipset, however at only 10-11 frames per second, you won’t be able to play Call of Duty 4 with these integrated video solutions, even when setting all image quality settings to their minimums.

When we installed a GeForce GT 430, the three CPUs achieved the same performance level.

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 1440×900. 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.

Let’s compare the results using the chipset integrated graphics first. On this game the Phenom II X4 840 with the AMD 880G chipset was 15% faster than the Pentium E6800 with the Intel G45 chipset. However, at 18-21 frames per second, you will cry trying to play StarCraft II with these integrated video solutions, even when setting all image quality settings to their minimums.

When we installed a GeForce GT 430, the three CPUs achieved similar performance levels.

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 1440 x 900, 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.

Let’s compare the results using the chipset integrated graphics first. On this game the Phenom II X4 840 with the AMD 880G chipset was 50% faster than the Pentium E6800 with the Intel G45 chipset. However, at 14-21 frames per second, you will cry trying to play Far Cry 2 with these integrated video solutions, even when setting all image quality settings to their minimums.

When we installed a GeForce GT 430, the Phenom II X4 840 was 4% faster than the Pentium E6800.

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 this game at 1440×900 with graphics set at “low,” with no anti-aliasing and no anisotropic filteri
ng. The results below are the number of frames per second generated by each system.

Since the integrated graphics engine of the Intel G45 and AMD 880G chipsets aren’t DirectX 11, we had to run this game in DirectX 9 mode in order to compare the performance of the integrated video. Under this scenario, the Phenom II X4 840 with the AMD 880G chipset was 34% faster than the Pentium E6800 with the Intel G45 chipset. However, at 7-9 frames per second, it is impossible to play Lost Planet 2 with these integrated video solutions, even when setting all image quality settings to their minimums.

Installing a GeForce GT 430 video card, we were able to run this game in DirectX 11 mode. Here the Phenom II X4 840 was 5% faster than the Pentium E6800 and 16% faster than the Athlon II X4 635.

3DMark 11 Professional measures Shader 5.0 (i.e., DirectX 11) performance. Since the integrated graphics engine of the Intel CPUs and AMD 880G chipset aren’t DirectX 11, the only way to run this game was by installing an add-on video card. We used a GeForce GT 430 video card, which is an entry-level DirectX 11 video card. We ran this program at 1440×900 using the “Performance” profile.

This program provides three different scores: graphics, physics and combined.

The graphics score of the Phenom II X4 840 was 13% higher than the one achieved by the Pentium E6800.

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 Phenom II X4 840 was 11% faster than the Pentium E6800.

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

We did some basic overclocking with the Phenom II X4 840. All the other components were the same, using a GeForce GT 430 video card. We ran Far Cry 2 to test the system stability (i.e., to make sure the system wasn’t crashing).

The Phenom II X4 840 works internally at 3.2 GHz, which is achieved by multiplying its 200 MHz base clock by 16. Since this CPU has its clock multiplier lock, the only way to overclock it is by increasing its base clock.

The CPU default voltage is 1.3950 V, and we increased it to 1.4000 V.

We could increase the CPU base clock up to 237 MHz, making the CPU to run internally at 3,792 MHz, an 18.5% increase on its default internal clock rate, a very good result.

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

While Intel is the one that releases the fastest high-end CPUs first, AMD still has the edge on the value segment. On the USD 100 price range there is no better CPU than the new Phenom II X4 840 (3.2 GHz). Its main competitor is the Pentium E6800 (3.33 GHz), which, using the socket LGA775, may be considered by many as an outdated CPU. The cheapest Core i3 available, the 530, costs USD 120, being 20% more expensive than the Phenom II X4 840, thus not competing with this new CPU.

The Phenom II X4 840 also has a very good overclocking capability, and will also please the overclockers with a limited budget.

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For Performance

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