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Enter The Dragon: AMD Phenom II X4 940
Date: Jan 08, 2009
Author: Marco Chiappetta
Introduction and Specifications

AMD has been fighting an uphill battle on two fronts for the last few years. For a time, fierce competition from NVIDIA, coupled with some of their own problems executing, put the ATI graphics division in a deep hole. And ever since the introduction of the original Core 2 processors, and more recently the Core i7, AMD's processor division has fallen well behind Intel in terms of overall performance.

Starting in November of 2007 though, we got a sense that AMD was slowly, but surely, clawing its way back into the fight. It began with the introduction of the Spider platform, which consisted of AMD's native quad-core Phenom processors, 7-series chipsets, and 3800-series graphics cards. Individually, the components that made up the Spider platform weren't performance leaders in their respective categories, but ultimately the platform proved to be solid, and of course, it was priced very competitively. The introduction of Spider also marked the first time AMD could offer an entire desktop platform consisting only of AMD-branded processors, core logic, and graphics.

As many of you know, AMD hasn't been sitting idle since the Spider platform introduction. The company's chipset division has launched a handful of new chipsets, featuring one of--if not--the best IGPs on the market and a new Southbridge, the SB750, that allows for higher overclocks through the use of ACC, or Advanced Clock Calibration. The ATI graphics division has also been firing on all cylinders lately, having released a top to bottom lineup of GPUs that compete very favorably at their respective price points. AMD also recaptured the 3D performance crown from NVIDIA for a time with the Radeon HD 4870 X2. AMD wasn't going down without a fight.

With the chipset and graphics divisions on a roll, it was time for the CPU team to pull the trigger on something new and exciting, to complete the new platform trifecta. It took some time, but that's exactly what's happening today. The end result is the Dragon platform which consists of new 45nm Phenom II X4 processors, 7-series chipsets, and ATI Radeon 4000 series graphics cards. We've got the goods in house and will fill you in on all of the juicy details on the pages ahead; for now let's get some of the particulars and back-story out of the way...

AMD Dragon Platform

AMD Phenom II X4 Processors 
Specifications and Features

Model / Processor Frequency: AMD Phenom II Processor Model X4 940 / X4 920 / 3.0GHz, 2.8GHz
L1 Cache Sizes: 64K of L1 instruction and 64K of L1 data cache per core (512KB total L1 per processor)
L2 Cache Sizes: 512KB of L2 data cache per core (2MB total L2 per processor)
L3 Cache Size: 6MB (shared)
Memory Controller Type: Integrated 128-bit wide memory controller, capable of being configured for dual 64-bit channels for simultaneous read/writes
Memory Controller Frequency: Up to 1.8GHz with Dual Dynamic Power Management
Types of Memory: Support for unregistered DIMMs up to PC2 8500 (DDR2-1066MHz)
HyperTransport 3.0: One 16-bit/16-bit link @ up to 3600MHz full duplex
Total Processor Bandwidth: Up to 31.5 GB/s bandwidth
Packaging: Socket AM2+ 940-pin organic micro pin grid array (micro-PGA) (backward compatible with Socket AM2)
Fab location: AMD's Fab 36 wafer fabrication facilities in Dresden, Germany
Process Technology: 45nm (.045-micron) DSL Silicon on Insulator (SOI)
Approximate Transistor count: approx. ~758 million (65nm)
Approximate Die Size: 258 mm2 (45nm)
Nominal Voltage: .0875-1.5 Volts
Max Ambient Case Temp: 62 degress Celsius
Max TDP: 125 Watts
ACP: *to be announced after launch
Future Memory Controller Note: Future 45nm processors versions are planned to include support for DDR3 memory

Although the Dragon platform as a whole is new, most of its parts have already been on the scene for quite some time now. As such, we have already covered them in-depth here on HotHardware, so we won't do the same again here. We will, however, recommend taking a look at a few past articles to get familiar with some of the underlying technology and components that partially comprise the Dragon platform.

The Radeon HD 4800 series articles detail the features and technology that have made them so successful in the 3D graphics space. And the various 7-series chipset, Phenom and Athlon processor, and Spider platform related articles cover the remainder of the platform--with the exception of the Phenom II that is, which we'll show you next.

The AMD Dragon Platform


AMD's new baby is the Phenom II X4 line-up of desktop processors. Like the original Phenoms that came before it, the new Phenom II X4 processors feature a native quad-core design, with a shared L3 cache, and they fit into current AM2+ sockets. There are quite a few changes under the hood, however, that give Phenom II processors a significant edge is power efficiency and performance over their predecessors, and there are more changes to come in the not too distant future. 

AMD Phenom II Architecture and Platform Details

The most significant change brought forth with the Phenom II X4 is AMD's use of a 45nm fabrication process to manufacture the chips. The transition to 45nm helped reduce power consumption somewhat, but has also allowed AMD to up the L3 cache to 6MB, while simultaneously shrinking the die to 258mm2 (65nm Phenoms are 285mm2). In addition to the 45nm switch, AMD also re-architected the execution cores to offer higher IPC through enhancements to the architecture, brand predictors, and remapping of the cores within the die. According to AMD, the changes made to the cache and execution cores offer up to 5% and 3% performance improvements, respectively, over the original Phenom design.

Also new to the Phenom II X4 series is a DDR2 and DDR3 compatible integrated memory controller. The first batch of Phenom II processors, like the ones we're looking at today, however, will only work with DDR2 memory. Finally, the new Phenom II X4 processors will be offered at higher frequencies than existing models. The Phenom II X4 920 and 940 we'll be showing you here are clocked at 2.8GHz and 3.0GHz, respectively. The 940 also happens to be a "Black Edition" processor, that ships with unlocked multipliers, for easier overclocking.

Speaking of overclocking, AMD has been touting the frequency headroom in these new processors from quite some time.  In fact, at a recent event, we saw one overclocked to over 5GHz--a vast improvement over the 65nm Phenoms.  We didn't quite get our sample to go that high, but still hit some respectable numbers.  More on that on the next page.

AMD Phenom II X4 940 Black Edition

As we've already mentioned, the first two Phenom II X4 processors to be introduced will use the same AM2+ packaging as existing Phenom processors. That means these new chips will be compatible with existing DDR2 platforms, after a BIOS update of course. Future Phenom II processors will employ AMD's socket AM3, which will usher in support for DDR3 memory.

We should note, that future AM3-based Phenom II X4 processors will be backwards compatible with AM2 and AM2+ platforms, and work with DDR2 or DDR3 memory types. But these current AM2+ Phenom II X4 processors will not be forward compatible with AM3/DDR3 platforms.

Phenom II Vital Signs and Overclocking

As we showed you on the previous page, the new Phenom II X4 processors look just like the original Phenoms, or older Athlons for that matter. But we fired up the latest version of CPU-Z to take a look at our Phenom II X4 940 processor's inner workings, because there are some distinct differences with the underlying technology.

AMD Phenom II X4 940 CPU-Z Details

CPU-Z correctly identifies the processor as a Phenom II, based on the core codenamed "Deneb". As the information shows, the chip is manufactured using AMD's 45nm process technology and our particular sample has a stepping designation of 2 and revision of RB-C2. The chip is clocked at 3GHz, due to its 15x multiplier and 200MHz base clock, the HT link is running at 1.8GHz, and there is 512K of L1 Data / Instruction cache, 2MB of L2 cache (512K per core), and 6MB of shared L3 cache.

Overclocking The Phenom II X4 940
Pedal To The Metal

AMD Phenom II X4 940 Overclocked to 3.73GHz

With all of the information AMD has already revealed regarding the Phenom II's overclockability, we were eager to see what our particular chip could do. We didn't use any exotic cooling for our overclocking experiments, opting instead to see just how far the chip would go with a stock AMD PIB air cooler installed. With only a minor bump in voltage to 1.575v, we were able to take our particular CPU to almost 3.8GHz using the stock air cooler alone. That speed was achieved with an 18.5x multiplier and a 202MHz base clock; the components were installed in a basic mid-tower. The AMD Overdrive utility shown in the screenshot above did not report clock speeds correctly, but assuming thermal readings were correct (we don't think they were), the chip ran at about 50'C while overclocked.

Our Test Systems and SiSoft SANDRA


How We Configured Our Test Systems: When configuring our test systems for this article, we first entered their respective system BIOSes and set each board to its "Optimized" or "High performance Defaults". We then saved the settings, re-entered the BIOS and set memory timings for either DDR2-1066 (AMD) with 5,5,5,15 timings or DDR3-1333 with 7,7,7,20 timings (Intel). The hard drives were then formatted, and Windows Vista Ultimate was installed. When the Windows installation was complete, we updated the OS, and installed the drivers necessary for our components. Auto-Updating and Windows Defender were then disabled and we installed all of our benchmarking software, defragged the hard drives, and ran all of the tests.

 HotHardware's Test Systems
 Intel and AMD - Head To Head 

System 1:
AMD Phenom II X4 940

(3.0GHz Quad-Core)
AMD Phenom II X4 920
(2.8GHz Quad-Core)
AMD Phenom X4 9950
(2.6GHz Quad-Core)

MSI DKA790GX Platinum
(AMD 790GX Chipset)

2x2GB Corsair PC2-8500
CL 5-5-5-15 - DDR2-1066

GeForce GTX 280
On-Board Ethernet
On-board Audio

WD150 "Raptor" HD
10,000 RPM SATA

Windows Vista Ultimate
NVIDIA Forceware v180.43
DirectX Redist (August 2008)

System 2:
Core 2 Extreme QX9770

(3.2GHz - Quad-Core) 
Core 2 Extreme QX9650
(3.2GHz - Quad-Core)

Core 2 Quad Q9400
(2.66GHz - Quad-Core)

Asus P5E3 Premium
(X48 Express Chipset)

4x1GB Corsair DDR3-1800
CL 7-7-7-20 - DDR3-1333

GeForce GTX 280
On-Board Ethernet
On-board Audio

WD150 "Raptor" HD
10,000 RPM SATA

Windows Vista Ultimate
NVIDIA Forceware v180.43
DirectX Redist (August 2008)

System 3:
Core i7 Extreme 965

(3.2GHz - Quad-Core)
Core i7 940
(2.93GHz - Quad-Core)
Core i7 920
(2.66GHz - Quad-Core)

Intel DX58SO
(X58 Express Chipset)

3x1GB Qimonda DDR3-1066
CL 7-7-7-20 - DDR3-1066

GeForce GTX 280
On-Board Ethernet
On-board Audio

WD150 "Raptor" HD
10,000 RPM SATA

Windows Vista Ultimate
NVIDIA Forceware v180.43
DirectX Redist (August 2008)

 Preliminary Testing with SiSoft SANDRA XII SP2a
 Synthetic Benchmarks

We began our testing with SiSoftware's SANDRA XII, the System ANalyzer, Diagnostic and Reporting Assistant. We ran six of the built-in subsystem tests that partially comprise the SANDRA XII suite with AMD's new Phenom II X4 940 processor (CPU Arithmetic, CPU Multimedia, Multi-Core Efficiency, Memory Bandwidth, Cache and Memory Bandwidth, and Memory Latency).  All of the scores reported below were taken with the processor running its default clock speeds of 3.0GHz, with 4GB of DDR2-1066 RAM running in unganged mode.

Processor Arithmetic
Phenom II X4 940

Phenom II X4 940

Multi Core Efficiency
Phenom II X4 940

Memory Latency
Phenom II X4 940

Cache & Memory
Phenom II X4 940

Memory Bandwidth
Phenom II X4 940

The various SiSoft SANDRA tests we ran paint the Phenom II X4 940 in a somewhat favorable light.  The chip was the fastest of all of the AMD-based systems by bar, and it held its own against the similarly clocked, Penryn-based Intel Core 2 Quad Q9650, although the Q9650 was faster overall.  The Core i7-based systems simply extended the lead held by the Core 2 Quads.

In the memory bandwidth tests, the Phenom II X4 940 offered up 12GB/s of bandwidth with DDR2-1066 memory attached.  It's going to be interesting to see how that numbers changes when the DDR3-enabled AM3 editions of these processors are released later this year, with potentially higher frequencies.

PCMark Vantage

We ran a handful of processors and platforms, including the new Phenom II X4 940 and 920, through Futuremark‚Äôs latest system performance metric built especially for Windows Vista, PCMark Vantage. PCMark Vantage runs through a host of different usage scenarios to simulate different types of workloads including High Definition TV and movie playback and manipulation, gaming, image editing and manipulation, music compression, communications, and productivity.  Most of the tests are multi-threaded as well, so the tests can exploit the additional resources offered by a quad-core CPU.

Futuremark PCMark Vantage
Simulated Application Performance

AMD's new Phenom II X4 940 and 920 processors performed very well in PCMark Vantage.  The most interesting comparison is between the similarly clocked 3.0GHz Q9650 and the X4 940.  In a direct comparison, the Core 2 Quad Q9650 outperforms the Phenom II in the the Music and Memories tests.  The Gaming test was a virtual tie between the two, and the Phenom II takes the rest.  The Phenom II holds its own against the Core i7 920 in a few tests too, but gets smoked in the gaming test.

LAME MT and Kribibench v1.1

In our custom LAME MT MP3 encoding test, we convert a large WAV file to the MP3 format, which is a popular scenario that many end users work with on a day-to-day basis to provide portability and storage of their digital audio content.  LAME is an open-source mid to high bit-rate and VBR (variable bit rate) MP3 audio encoder that is used widely around the world in a multitude of third party applications.

Audio Encoding

In this test, we created our own 223MB WAV file (a hallucinogenically-induced Grateful Dead jam) and converted it to the MP3 format using the multi-thread capable LAME MT application in single and multi-thread modes. Processing times are recorded below, listed in seconds. Once again, shorter times equate to better performance.

The new Phenom II 920 and 940 are clearly the fastest AMD processors in our LAME encoding tests, but they can't quite catch Intel's Core 2 Quads or Core i7 processors.  Even the 2.66GHz Q9400 outpaces the 3.0GHz Phenom II X4 940 here. 

Kribibench v1.1
CPU-Bound 3D Rendering

For this next batch of tests, we ran Kribibench v1.1, a 3D rendering benchmark produced by the folks at Adept Development.  Kribibench is an SSE aware software renderer in which a 3D model is rendered and animated by the host CPU and the average frame rate is reported.  We used two of the included models with this benchmark: a "Sponge Explode" model consisting of over 19.2 million polygons and the test suite's "Ultra" model that is comprised of over 16 billion polys.

Once again, the new Phenom II processors are unable to catch their Intel-built competitors.  Interestingly, the Phenom X4 9950 pulls ahead of the X4 920 here, likely due to the 9950's higher clocked memory controller, which offers up more bandwidth.  The Phenom II X4 940's much higher core clock allows it to overcome the bandwidth deficit, however.

Cinebench R10 and POV-Ray

Cinebench R10 is an OpenGL 3D rendering performance test based on Cinema 4D from Maxon. Cinema 4D is a 3D rendering and animation tool suite used by 3D animation houses and producers like Sony Animation and many others.  It's very demanding of system processor resources and is an excellent gauge of pure computational throughput.

Cinebench R10
3D Rendering

This is a multi-threaded, multi-processor aware benchmark that renders a single 3D scene and tracks the length of the entire process. The rate at which each test system was able to render the entire scene is represented in the graph below.

Our results with the Cinebench R10 benchmark tell much of the same story.  The new Phenom II X4 processors clearly outperform their AMD-built predecessors, but they can't quite catch the Core 2 or Core i7s in either the single or multi-threaded tests. 

POV-Ray Performance
Ray Tracing

POV-Ray , or the Persistence of Vision Ray-Tracer, is a top-notch open source tool for creating realistically lit 3D graphics artwork. We tested with POV-Ray's standard 'all-CPU' benchmarking tool on all of our test machines, and recorded the scores reported for each. Results are measured in pixels-per-second throughput; higher scores equate to better performance.

The results obtained with the POV-Ray benchmark essentially mirror those of Cinebench above.  The new Phenom II X4 920 and 940 easily outpace the older, 65nm Phenom X4 9950, but Intel's Core 2 Quads--with the exception of the Q9400--and Core i7s take the overall lead regardless of frequency.

3DMark06 and Vantage CPU Tests

3DMark06's built-in CPU test is a multi-threaded DirectX gaming metric that's useful for comparing relative performance between similarly equipped systems.  This test consists of two different 3D scenes that are processed with a software renderer that is dependent on the host CPU's performance.  Calculations that are normally reserved for your 3D accelerator are instead sent to the CPU for processing and rendering.  The frame-rate generated in each test is used to determine the final score.

Futuremark 3DMark06
Synthetic DirectX Gaming

At the risk of sounding like a broken record, 3DMark06's built-in CPU benchmark reported scores in-line with our previous tests.  The new Phenom IIs performed well, outpacing the older 9950, but Intel's Core 2 and Core i7 processors retained their lead, except for the Q9400 that is, which was barely edged out by the Phenom II 940. 

Futuremark 3DMark Vantage
Synthetic DirectX Gaming

3DMark Vantage's CPU Test 2 is a multi-threaded test designed for comparing relative game physics processing performance between systems.  This test consists of a single scene that features an air race of sorts, with a complex configuration of gates. There are aircraft in the test that trail smoke and collide with various cloth and soft-body obstacles, each other, and the ground. The smoke spreads, and reacts to the planes as they pass through it as well and all of this is calculated on the host CPU. 


3DMark Vantage's CPU Test 2 benchmark proved to be somewhat of a strong point for AMD's new baby.  Here, the Phenom II's hung right alongside Intel's best, regardless of frequency.

Gaming: Crysis and F.E.A.R.

For our next set of tests, we moved on to some in-game benchmarking with Crysis and F.E.A.R. When testing processors with Crysis or F.E.A.R., we drop the resolution to 800x600, and reduce all of the in-game graphical options to their minimum values to isolate CPU and memory performance as much as possible.  However, the in-game effects, which control the level of detail for the games' physics engines and particle systems, are left at their maximum values, since these actually do place some load on the CPU rather than GPU.

Low-Resolution Gaming: Crysis and F.E.A.R.
Taking the GPU out of the Equation

Crysis and F.E.A.R. told constrasting stories.  In the Crysis CPU benchmark, the new Phenom II X4 processors smoked the Phenom X4 9950, but fell victim to every Intel CPU.  The story is very different in F.E.A.R., however, where the Phenom II X4 940 put up the best score of the bunch and the X4 920 squeaked by the Core 2 Extreme Q9650 and Core i7 920.

Power Consumption

We'd like to cover a few final data points before bringing this article to a close. Throughout all of our benchmarking and testing, we monitored how much power our test systems consumed using a power meter. Our goal was to give you all an idea as to how much power each configuration used while idling and while under a heavy workload. Please keep in mind that we were testing total system power consumption at the outlet here, not just the power being drawn by the processors alone.

Total System Power Consumption
Tested at the Outlet

When coupled to AMD's 790GX motherboard platform, the new Phenom II X4 940 and 920 proved to be quite power friendly.  They offered the lowest idle power consumption of the bunch and peak consumption was lower than all of the Intel-based systems with the exception of the lower-clocked Core 2 Quad Q9400.

Our Summary and Conclusion

Performance Summary: The new Phenom II X4 920 and 940 are easily the most powerful desktop processors released from AMD to date. They performed well throughout our entire battery of benchmark tests, besting AMD's previous flagship CPU, the Phenom X4 9950 virtually across the board. Unfortunately, the new Phenom II X4 920 and 940 could quite keep pace with Intel's Penryn-based Core 2 Quads or Nehalem-based Core i7s. The Phenom II X4 managed to pull ahead of the Q9400, Q9650, and i7 920 on a few instances, but overall Intel's platform was still faster. The gap has closed quite a bit, however.

We get the feeling these first two Phenom II X4 processors are just the tip of the iceberg. If our overclocking results are any indicator, AMD will likely be ramping up clock speeds on the Phenom II in the not too distant future, most likely when the DDR3-capable versions are ready. There's a good probability the next spin of these chips will be able to hit higher frequencies, that, in addition to the increased bandwidth that will be afforded by DDR3 memory, and potentially some tweaks on the chipset / motherboard level, should push the Dragon platform's overall performance up a few more percentage points, which will put them right on top of Intel's Core 2. Time will tell. 

For now, expect the Phenom II X4 940 and 920 to hit store shelves with prices of $275 and $235, respectively. That puts them right on par pricewise with the Q9400, which is about where they should be. The total cost of ownership, however, will still be somewhat lower with the Dragon platform though, as 7-series motherboards and DDR2 memory are quite affordable at this time. These new chips will also drop into most existing AM2+ platforms, which may make them attractive upgrade options to current AMD owners--if your current motherboard supports 125W (or higher) Phenoms, it should support Phenom II as well. 



  • Highly Overclockable
  • Low Power Consumption
  • Strong Performance
  • Affordably Priced
  • Not Quite as Fast as Core 2
  • Phenom II X4 920 and 940 not AM3 DDR3 compatible

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