AMD Phenom II X4 955 AM3 CPU Review

ajmatson - 2008-05-09 15:23:33 in CPU's
Category: CPU's
Reviewed by: ajmatson   
Reviewed on: April 22, 2009
Price: $245


AMD has been busy with their motherboard chipset and processor releases this year. At CES, we took a look at the new Phenom II series beginning with the Phenom II X4 940, which was an AM2+ processor with a lot of attitude and a new level of performance and overclocking ability than we have seen from the Phenom series CPUs. Fast forward a bit, and AMD has been releasing socket AM3 processors, which support the faster DDR3 memory standard. Today we are going to be taking a look at one new AM3 processor, the AMD Phenom II X4 955. The new Phenom II 955 processor takes on the success of the Phenom II 940 and builds on it for faster, bleeding-edge performance. The AMD Phenom II X4 955 is clocked at 3.2GHz, and has a total L2 and L3 cache of 8MB. As with other AM3 processors, the Phenom II 955 can be used in both AM2+ and AM3 motherboards, supporting DDR2 1066MHz and DDR3 1333MHz memory on a 128-bit wide memory controller. Now that I have you drooling, let's move on and look closer at the CPU itself.


Closer Look:

Since this is a review sample, the processor is shipped to us in an anti-static box sandwiched between foam. The retail versions will come in a more secure package, along with the heatsink fan for cooling.






At first glance, the Phenom II X4 955 looks like any other Phenom II - minus the different codes stamped on it for identification. Again, this is an AM3 processor, which has uses a 938 micro-pin grid array (micro-PGA) configuration. The Phenom II 955 is manufactured using a 45nm process, has 758 million transistors and has a maximum TDP of 125 watts, using a voltage of 0.875 - 1.5v with a maximum operating temperature of 68C degrees. The 955 also supports HyperTransport 3.0 for up to 37.3GB/s when paired with DDR3 1333MHz memory, and 33.1GB/s when paired with DDR2 1066MHz memory. The cache breakdown for L2 is 2MB, which translates to 512KB per core, and the L3 is 6MB shared between each of the cores. The Phenom II X4 955 is clocked at 3.2GHz (200MHz x 16), and is a "Black Edition" processor - meaning that the multiplier is unlocked, so higher overclocks can be attained with the right tweaking.



Now that we have explored the new processor, we can plug it in and see what this baby can do.



Model Number:
X4 955
Clock Frequency:


Max TDP:
125 watts
Cache Size:
L1 Cache 64K (each for Instruction + Data)
L2 Cache: 512KB per core
L3 Cache: 6MB Shared L3
Process Technology:
45-nanometer SOI (silicon-on-insulator) technology
HyperTransport Technology Links:
One 16-bit/16-bit link @ up to 4.0GHz full duplex (2.0GHz x2)
Integrated 128-bit wide memory controller with speeds: Up to 2.0GHz with Dual Dynamic Power Management
Types of Memory:
support unregistered DIMMs up to PC2-8500 (DDR2-1066MHz) -AND- PC3-10600 (DDR3-1333MHz)
Die Size:
45nm = 258mm 
45nm = 758million
Socket AM3 - 938-pin organic micro Pin Grid Array (micro-PGA) (Backwards compatable with AM2+ 940-pin)







To test the strengths and weaknesses of the new Phenom II X4 955 processor, I put it through a series of benchmarks that test the scientific and video processing capabilities. To give you a comparison to mainstream processors being used currently, I included the AMD Phenom II X4 940 and the Intel Core i7 920 processor scores. This will give you an idea where the X4 955 sits between Intel's current leader and AMD's DDR2 leading processor. All hardware used was set to its native operating speeds, timings, and voltages to keep any variables from interfering with the scores. Because of time constraints and hardware availability, the video testing phase will have some of the newer chips included, however not all of them will be shown.


Testing Setup AMD AM3 CPU:


Testing Setup AMD AM2+ CPU:


Testing Setup I7 CPU's:


Testing Setup Core2 CPU's:


Comparison CPUs:



Overclocked settings:

Overclocking the Phenom II X4 955 was a lot more tedious than when I reviewed the X4 940. This processor did not like being pushed very far, no matter how much voltage I threw at it. I expected to at least be able to get 4GHz out of it, after the easily overclockable 940, but boy was I mistaken. When it came to the multiplier, anything over x18.5 and the computer would not boot at all. Even pushing the voltage on the CPU, NB and the HT I could not get any more out of it. Pushing the FSB, the system would lock up at anything past 205Mhz. It just did not want to budge. I even raised the voltages over safe operating limits and still no joy. So the final settings I ran for the overclock were 3.795GHz at 1.5v and memory speeds of 1366MHz at 7-7-7-20 timings.







  1. Apophysis
  2. WinRAR
  3. SPECviewPerf 10
  4. PCMark Vantage Professional
  5. Sandra XII
  6. ScienceMark 2.02
  7. Cinebench 10
  8. HD Tune 2.55
  1. Far Cry 2
  2. Crysis Warhead
  3. BioShock
  4. Call of Duty World At War
  5. Dead Space 
  6. Fallout 3 
  7. Left 4 Dead
  8. 3DMark 06 Professional
  9. 3DMark Vantage


The first part of our testing will be the system specific benchmarks.


Let's get started with Apophysis. This program is used primarily to render and generate fractal flame images. We will run this benchmark with the following settings:



The measurement used is time to render, in minutes, to complete.






Lower is Better


WinRAR is a tool to archive and compress large files to a manageable size. We will use 10MB, 100MB and 500MB files and test the time needed to compress these files. Time will be measured in seconds.










The AMD Phenom II X4 955 did better than the older generation in the Apophysis and RAR portion of the WinRAR testing, but not as well as the Intel Core i7 920. The Phenom II X4 940 performed at a higher level than the 955 in the ZIP portion of the WinRAR testing. The extra bandwidth from the use of DDR3 memory seems to have helped it along in the tests that took longer to complete.


SPECviewperf 10 is a benchmark designed to test OpenGL performance. I will be using the multi-threaded tests to measure the performance when run in this mode. The tests used for comparison are listed below. The default multi-threaded tests were chosen to be able to compare across platforms. In these tests, higher scores equate to better performance.

















Higher is Better


PCMark Vantage is used to measure complete system performance. We will be running a series of tests to gauge performance of each individual CPU to see which CPU, if any, rises above the others.


For SPECview, the Phenom II X4 955 was beaten in all six the tests by the Phenom II 940 . For PCMark Vantage, the 955 was slightly better than the Phenom II 940 and the Q9450, but still behind the Core i7 920.


SiSoft Sandra is a diagnostic utility and synthetic benchmarking program. Sandra allows you to view your hardware at a higher level to be more helpful. For this benchmark, I will be running a broad spectrum of tests to gauge the performance of key functions of the CPUs.












Processor Arithmetic


Multi-Core Efficiency


Memory Bandwidth


Memory Latency


Cache and Memory


File System


Physical Disks


Power Management Efficiency


The Phenom II 955, for the most part, scored better then the Phenom II 940 - with the highlights being the memory bandwidth delivered, the memory latency and the power management efficiency. However, it scored far behind the Intel Core i7 processor in many of the benchmarks.


ScienceMark tests real world performance instead of using synthetic benchmarks. For this test, we ran the benchmark suite and will use the overall score for comparison.













Higher is Better!


CineBench is useful for testing your system, CPU and OpenGL capabilities using the software program CINEMA 4D. We will be using the default tests for this benchmark.


Higher is Better


HD Tune measures disk performance to make comparisons between drives or disk controllers.


Higher is Better



Lower is Better


In ScienceMark, the Phenom II 955 scored the best among the other processors, due in part to the increase clock speed. For CineBench and HD Tune, the Phenom II  955 scores better than the Phenom II 940, and worse than the Core i7 920.


Far Cry 2:

Featuring a new game engine named Dunia, this game looks to be another one to stress your video card. Built especially for Far Cry 2, this engine allows for real time effects and damage. This next generation First Person Shooter comes to us from Ubisoft surprisingly - not from Crytek. The game is set in a war-torn region of Africa where there is a non-existent central government and the chaos that surrounds this type of social environment. If you have seen the movie Blood Diamond, you know the setting. Ubisoft puts the main storyline of the game into focus with these statements: "Caught between two rival factions in war-torn Africa, you are sent to take out "The Jackal," a mysterious character who has rekindled the conflict between the warlords, jeopardizing thousands of lives. In order to fulfill your mission you will have to play the factions against each other, identify and exploit their weaknesses, and neutralize their superior numbers and firepower with surprise, subversion, cunning and, of course, brute force." In this version of the game, you don't have the beautiful water, but instead the beauty and harshness of the African continent to contend with. Most games give you a set area that can be played through, while Ubisoft has given the gamer the equivalent of 50km squared of the vast African continent to explore while in pursuit of your goals. The settings used are just a few steps below the maximum in-game settings and offer a good blend of performance vs. visual quality.








The Phenom II 955 scored above the comparison processors.


Crysis Warhead is a standalone expansion pack situated in time with the story line of the original Crysis. As Sergeant "Psycho" Sykes, you have a secret mission to accomplish on the far side of the island. Along the way ,there are EMP blasts and aliens to contend with, as you hunt down the KPA chief. This game uses an enhanced version of the CryEngine 2.














The scores were, for the most part, on par - except for the highest resolution where the 955 was a frame slower.


BioShock is one of the creepier games you can play. The building of a perfect Utopian society undersea gone horribly wrong. Its inhabitants driven mad with the introduction of tonics and genetic modifications. Now Rapture is just a shadow of its former glory with little girls looting the dead of what little they have left while being shadowed by guardians known as "Big Daddies". It is a demanding game that will make your hardware scream for mercy. This First Person Shooter allows for an infinite number of weapons and modifications to provide a unique experience each time it is played. The environment, as well as the story line, will wrap you up for hours on end.


Video Settings:











Again, the 955's scores were on par at the higher resolutions, and slightly ahead at the lower ones.


Activision's Call Of Duty World at War goes right back to the bread and butter of the franchise - WWII FPS action. In this rendition, you start off in the South Pacific and move through a series of missions that flip back and forth between the Russian front and the island hopping advance toward the Imperial Japanese homeland. Included is a mission on Peliliu Island, arguably one of the more difficult and costly battles in the Pacific theater. The gameplay in the single player mode is rather short, but the game makes up for this shortcoming in online gameplay. If you thought COD4 looked nice, this game is amazing with the graphics maxed out playing at a large resolution. This game just may be my reason to move to a 30 inch monitor. I will use Fraps to measure a section of gameplay in the Semper Fi map on Makin Island to compare performance of these video cards.













The 955 was a bit ahead of the 940, and a little behind the i7.


In Dead Space, as part of the crew of the USG Kellion, you are headed on a repair mission to repair a ship in distress. Things go from bad to worse as starting with the crash landing and seemingly silent and "Dead" ship, the USG Ishimuru. Offering a non-traditional over the shoulder viewing angle, the game gets right into the action as soon as the ventilation systems are activated. From there things get worse with the appearance of the Necromorphs. Survival now becomes a primary concern for the primary character Isaac Clarke. Survive and you may find the loved one that was aboard the Ishimuru.













The numbers were again so close, except at 1024x768, where the i7 blew everything away.


Fallout 3 takes place after the nuclear holocaust that nearly wipes out civilization and leaves the world an irradiated mess. The vault, or fallout shelter, you are born in is Vault 101, situated in the Washington DC, Maryland and Virginia area. The premise of the game is that the vault has been sealed for 200 years and now your father has opened the vault and escaped without a trace. The Overseer believes you are involved, so you must escape as well into the wasteland that was once our nation's capital. I find myself looking for landmarks, since I am familiar with the streets of Washington DC.













The 955 was faster then the other processors, but slower than the i7 again.


Left 4 Dead is a new release from Valve that leaves you as part of a group of survivors in a world where an infection has rapidly turned the populace into a zombie horde. You goal is to make it to a rescue point, all the while fighting what seems like overwhelming odds. Along the way there are safe houses where you can replenish your weapons and health. The movie 'I Am Legend' comes to mind to set the stage for this game. But unlike the movie, there are four characters, and not just a lone gun and his faithful companion. The horde is not at all like the typical slow walking, foot shuffling zombie. These zombies are quick and work with the pack mentality. Your job: survival!















All of the processors were too close to call, except for the Q9450, which the Phenom II 955 blew away.


3DMark06 is one of the benchmarks that always comes up when a bragging contest is started. 3DMark06 presents a severe test for many of today's hardware components. Let's see how this setup fares. The settings we will use are listed below.




















The AMD Phenom II X4 955 finished above the other processors - minus the i7 - except at the maximum resolution, where the Q9450 pulled a bit ahead also.


Featuring all-new game tests, this benchmark is for use with Vista based systems. "There are two all-new CPU tests that have been designed around a new 'Physics and Artificial Intelligence-related computation.' CPU test two offers support for physics related hardware." There are four preset levels that correspond to specific resolutions. 'Entry' is 1024x768 progressing to 'Extreme' at 1920x1200. Of course, each preset can be modified to arrange any number of user designed testing. For our testing, I will use the four presets at all default settings.













The newer AMD processors outperformed the older DDR2 AMD processors, however, it was far behind the Intel offering until the end, where they all came pretty close.


Overall, the AMD Phenom II X4 955 is a step in the right direction. During the majority of the scientific tests - which measure the CPU generally more than the rest of the system components - the Phenom II 955 outperformed the previous top AMD processor, the Phenom II X4 940, as well as the Intel Q9450 in most of the tests. While still not as fast as the Intel Core i7 920 processor, the Phenom II X4 955 is a well put together CPU that allows fast computing using the latest components on the market. Supporting both DDR2 and DDR3 based platforms, the Phenom II 955 gives you the flexibility to upgrade at your pace while having cutting edge components. Even in the video benchmarks, the Phenom II 955 gave a few frames per second increase over the Phenom II 940, which can mean the world with the resolutions of current monitors and the crisp 3D graphics that we all crave.

On the overclocking front, which OCC is all about, the Phenom II X4 955 lagged behind the Phenom II 940. No matter how much voltage I gave it, or how many adjustments I made, the CPU just did not want to budge. I attempted to suicide the voltage, and still the stability would not set in. With the Phenom II 940, I was able to get almost a 1GHz increase on air alone; however, with the Phenom II 955, the system would lock up with anything over 18.5x205Mhz. Since the Phenom II 955 is clocked higher than the Phenom II 940, it still has good overall speed when overclocked to almost 3.8GHz at 1.5 volts. With an expected release price of $245, the Phenom II 955 is still below the more expensive Core i7 920, and when you take into account the average price of a 790FX AM3 motherboard is $149, you can have a nice base for around $400 - versus the $500+ for an Intel Core i7 920 processor and X58 motherboard. And, you can still just purchase the Phenom II 955 and run it in your current AM2+ system for even less of an upgrade cost.