AMD Phenom II X4 975 BE and Phenom II X4 840 (Socket AM3) CPUs

AMD is kicking off the New Year with a pair of new CPUs - The Phenom II X4 975 BE and the Phenom II X4 840.

Manufacturer: AMD
12 minutes & 6 seconds read time


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AMD has been around for a long time in one form or another. When I first started working with AMD CPUs they were making 2x86 CPUs under license from Intel. Not too long after that they bought up a small and promising company named NexGen. From there things got interesting.

Before you knew it, AMD had a CPU that simply exploded onto the market and had a little bit of controversy surrounding a commercial put out by AMD at the time. This was the original Slot A Athlon CPU. With this one move (based on the DEC Alpha and in many ways both the EV6 and EV7 bus) AMD had a CPU that pulled them from the "value" market into the hearts of many enthusiasts.

Succeeding the original Athlon was the Opteron and the Athlon 64 which made 64-bit computing a household item. From there AMD began something of a slide when their next CPU offering (the Phenom) was not only delayed, but also had an unfortunate performance issue due to some TLB Errata.

AMD quickly recovered and brought us the Phenom II and Athlon II. These two CPUs have been slowly rebuilding AMD's reputation as a solid CPU designer. While not the first choice of most enthusiasts, AMD has never the less been climbing back into the game with a solid line-up of mainstream and value CPUs that can deliver some serious performance while not breaking the bank.

We have had the chance to try out two new "speed bumps" in the Phenom II line up - the 3.6GHz Phenom II X4 975 BE and the 3.2GHz Phenom II X4 840.

What's New and Overclocking Results

What's New

There really is nothing new to talk about here. Well ok. there is the fact that both of these got a slight speed increase over what is currently available in their lines. The 975 BE gets pushed to 3.6GHz while the 840 gets a bump to 3.2. Overall, not a bad increase, but we do want to see if this is all marketing or if it really means better performance for the consumer.

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Overclocking the Phenom II X4 975 BE was not all that hard. We simply tweaked the multiplier and also adjusted the core frequency a little bit (along with a small voltage bump) and we were off. The problem comes from the relatively low overclocks we are still getting.

On a 3.6GHz CPU we were unable to get over 4.2GHz that is only a bump of 600MHz. After the heydays of the Opteron and the Athlon 64 I am used to being able to get much more from AMD's CPU. However, since the introduction of the Phenom and Phenom II, this has simply not been the case.

Unfortunately we were not able to get to overclock the 840 as we ran up against a very frustrating issue with the Cat 10.12 drivers. However, we will be revisiting some AMD overclocking after CES is over with.

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You can check out the validation link for the new Phenom II X4 975 BE here.

Important Editor Note: Our maximum overclocking result is the best result we managed in our limited time of testing the motherboard. Due to time constraints we weren't able to tweak the motherboard to the absolute maximum and find the highest possible FSB, as this could take days to find properly. We do however spend at least a few hours overclocking every motherboard to try and find the highest possible overclock in that time frame. You may or may not be able to overclock higher if you spend more time tweaking or as new BIOS updates are released. "Burn-in" time might also come into play if you believe in that.

Test System Setup and Comments

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We would like to thank the following companies for supplying and supporting us with our test system hardware and equipment: GIGABYTE, ASUS, AMD, Corsair and Sceptre.

I did not have any issues with this pair of CPUs. Both worked very well on the GIGABYTE 890GPA-UD3H. The problem actually came with the Cat 10.12 drivers. For some reason this driver set would not allow 3DMark 11 to run with either of these CPUs installed. It was driving me absolutely crazy and almost caused this review not to be ready in time to meet today's launch.

Originally I was certain that the cause was the CPU, as the test would fail at the first Physics test which is when the CPU first comes into play. In the end, though, it turned out to be the 8.80 driver that is in the Cat 10.12 package.

Thankfully there is an 8.79.1 driver that is also hiding in there. I was able to install that and miraculously things started working again. Unfortunately, as we mentioned, this issue ate up the majority of our testing time so we can only give you half of the story on the 840 today.

Synthetic Tests - Part I

With any system you will want to see a combination of synthetic testing and real-world. Synthetics give you a static, easily repeatable testing method that can be compared across multiple platforms. For our synthetic tests we use Everest Ultimate, Sisoft Sandra, Futuremark's 3DMark Vantage and PCMark Vantage, Cinebench as well as HyperPi. Each of these covers a different aspect of performance or a different angle of a certain type of performance.

Memory Bandwidth

Memory is a big part of current system performance. In most systems slow or flakey memory performance will impact almost every type of application you run. To test memory we use a combination of Sisoft Sandra and HyperPi 0.99.

Sisoft Sandra

Version and / or Patch Used: 2011
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AMD still has some work to do on their memory bandwidth. We just cannot get the same performance out of these as we should be considering the speeds the memory is running at.

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Raw CPU performance is not bad for these two, especially when we kicked the 975 BE up to 4.2GHz.

HyperPi 0.99

Version and / or Patch Used: 0.99
Developer Homepage:
Product Homepage:
Download It Here

HyperPi is a front end for SuperPi that allows for multiple concurrent instances of SuperPi to be run on each core recognized by the system. It is very dependent on CPU to memory to HDD speed. The faster these components, the faster it is able to figure out the number Pi to the selected length.

For our testing we use the 32M run. This means that each of the four physical and four logical cores for the i7 and the four physical cores of the i5 is trying to calculate the number Pi out to 32 million decimal places. Each "run" is a comparative to ensure accuracy and any stability or performance issues in the loop mentioned above will cause errors in calculation.

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Here the performance is good for an AMD CPU. Remember that HyperPi is a memory killer, so with AMD's slower memory performance we are seeing some decent times. This means that the CPU can take it, but the memory speed just can't keep up.

Synthetic Tests - Part II

Here is where we dig out the FutureMark tests.

PCMark Vantage

Version and / or Patch Used:
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For overall system performance we use PCMark Vantage. This is run in both x86 and x64 mode to give the best indication of performance.

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Well look at this, the 975 BE actually does better in PCMark than the X6 1100T does. This could simply be the clock speed, though. Still, it is encouraging.

3DMark 11

Version and / or Patch Used: 1.0.1
Developer Homepage:
Product Homepage:
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For synthetic gaming tests we used the industry standard and overlockers bragging tool 3DMark 11. This is a test that strives to mimic the impact modern games have on a system. Futuremark went a long way to change from the early days of graphics driven tests to a broader approach including physics, AI and more advanced graphics simulations.

3DMark 11 uses the DX11 API in addition to having support for Physics run from the CPU, not PhysX. This will puts things on a semi neutral ground as neither GPU can gain an advantage from proprietary code.

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The numbers here are very interesting as we see these two CPUs give us very different results for these two quad core CPUs. Although there is only a 400MHz difference, there is a rather big delta between the numbers. We hope that this does not show up in gaming as it would put a dent on the 840's gaming ability no matter what the price.

Cinebench R11.5 x64

Version and / or Patch Used: R11.5 x64
Developer Homepage:
Product Homepage:
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Cinebench is a synthetic rendering tool developed by Maxon. Maxon is the same company that developed Cinema4D, another industry leading 3D Animation application. Cinebench R11.5 tests your systems ability to render across a single and multiple CPU cores. It also tests your systems ability to process OpenGL information.

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The two new Phenoms did not do so well here. As you can see, they just do not have the horse power to push into the top levels.

Real-World Tests - Part I

Real-world testing allows us to see how well a product will perform when used in the same manner as it would be in your house or office. It is an important side to performance testing as it can uncover hidden glitches in the way a product performs.

It is especially true when testing a mainboard; there are so many components of a board that have to interact that any problems between parts can cause a failure of the whole.

For real-world testing we use some common applications and functions. We test with LightWave 3D for rendering performance, AutoGK for transcoding from DVD to AVI and two games for gaming testing.


Rendering of 3D Animation is a system intensive endeavor. You need a good CPU, memory and HDD speed to get good rendering times. For our testing we use LightWave 3D. This software from Newtek is an industry standard and has several pre-loaded scenes for us to use.

LightWave 3D

Version and / or Patch Used: 9.6
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Again we see the two new Phenom X4 CPUs drop back in the standings. The 975 BE is still faster than a Core i5 750, but that does not take Sandy Bridge into account yet either.


Version and / or Patch Used: 2.55
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AutoGK stands for Auto Gordian Knot; it is a suite of transcoding tools that are compiled into an easy to install and use utility. It allows you to transcode non-protected DVDs and other media to Xvid or Divx format. For our testing purposes we use a non-DRM restricted movie that is roughly 2 hours in length. This is transcoded to a single Xvid AVI at 100% quality.

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The transcoding scores we find with the two new Phenoms are not impressive. Again this is mostly due to the slower memory performance that they have in comparison to the competition. If AMD can correct this issue we can see them discovering a serious performance gain.

Adobe Lightroom 2.7 x64

Version and / or Patch Used: 2.7
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This is a new test to TweakTown for CPUs, but it is one that we have been asked about by readers and also OEMs - using Adobe's Lightroom (or another application) to convert large raw images to JPEG.

For our testing we converted 100 15.1 Megapixel image files (just over 2GB of data) to the JPEG format (1280x853 resolution 72DPI) and timed how long it took to complete this. This test is a good real world test as more people take high resolution images and convert them for e-mail and the web.

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Converting raw images to JPG takes CPU power and memory speed. The fact that AMD does not have that yet shows here. But, think about this; if AMD had the same memory performance as the 875 (roughly twice currently), it would come very close to beating that CPU at a much smaller price.

Real-World Tests Part II

Here we have our real gaming tests. Each of the games we chose use multiple cores and GPUs. They are able to stress the system through use of good AI. Both have decent positional audio that adds impact to the sound subsystem of the board. We ran each game through the level or parts listed and recorded frames per second using FRAPS. This brings the whole game into play.

*** A word on gaming as a CPU test ***

Despite the fact that most games are very GPU limited, we are still noticing HDD and even audio creating issues in gaming performance. Because of this you may see differences in the number of frames rendered per second between different boards. Usually the difference is very small, but occasionally because of bad tracing, poor memory or HDD performance, this difference is significant. The issues are often more prevalent in older versions of DirectX, but can still pop up in DX10 and 11.

Call of Duty Modern Warfare 2 (DX9)

Version and / or Patch Used: 1.0
Timedemo or Level Used: First combat until the school is cleared
Developer Homepage:
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Most of you know about the game Modern Warfare 2; it caused quite a bit of controversy in the latter half of 2009. The game is a first person shooter with a heavy combat emphasis. It follows the events in the first Modern Warfare very closely and brings back several characters from the original.

As with most games in the Call of Duty franchise, it features a heavy AI load. This is not because of a complex AI routine, but more due to the sheer number of enemies in any given combat situation. It is also our single DX9 based game in our testing suite. Settings are shown below.

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As you might have guessed, gaming performance is not affected by the CPU with Modern Warfare 2. Even running from top to bottom and looking at averages there is less than a 20FPS difference. When you look at minimum it is even smaller. Plus, all of these are well over the 32FPS considered by most as full fluid motion.

Far Cry 2 (DX10)

Version and / or Patch Used: V1.00
Timedemo or Level Used: Clearing the Safe house through to the Rescue
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Far Cry 2 is a large sandbox style game. There are no levels here, so as you move about the island you are on you do not have to wait for the "loading" sign to go away. It is mission driven so each mission is what you would normally think of as the next "level".

In the game you take the role of a mercenary who has been sent to kill the Jackal. Unfortunately your malaria kicks in and you end up being found by him. Long story short, you become the errand boy for a local militia leader and run all over the island doing his bidding. Settings we used for testing are shown below.

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Far Cry 2 is a little more lopsided. Here we have an almost 40FPS delta between top and bottom when we look at the averages. However, once again we find that the minimum numbers are very close. The 975 BE and 840 come in near the bottom, but both are still more than playable.

Battlefield Bad Company 2 (DX11)

Version and / or Patch Used: V1.00
Timedemo or Level Used: From washing up on the beach to the mine fields.
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Battlefield Bad Company is another sequel and also another game "franchise". Bad Company 2 is also our DX11 Shooter game. The game follows a fictitious B company team on a mission to recover a Japanese defector. This puts you back in World War II (at least for the beginning of the game) while the multi-player game is centered on much more modern combat. For our testing we used the single player mode. Settings are shown below.

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Well now, look here; the new AMD CPUs come in at the top for Bad Company 2. Even using the minimums, they are doing quite well. But then again, this was an AMD sponsored game and it can combine the whole platform.

Gaming Conclusion

We keep saying this, but it bears repeating. The CPU is very seldom the bottle neck for your gaming. There are times when a slow CPU or improperly coded BIOS for your CPU will have an impact, but for the most part the GPU is the king here.

Both of the new Phenoms do well in gaming. If you are looking for a cheap gaming CPU with four cores, then these are probably worth looking at.

Final Thoughts

I have to say that I was a little disappointed with these two new CPUs. I guess I was hoping for a little more than was presented. After talking with a few people I was reminded that these are not new microarchitecture, but are revisions of an existing one.

In that respect, the 975 BE and the 840 do a pretty good job. They do have to address the memory performance issue, though. That is what is killing them. I am hoping for something exciting from AMD as we have been rehashing the same things for far too long now. I know that Fusion is right around the corner, but even that is aiming at the entry and mobile market and not the desktop.

In the end, we can say that both of these CPUs perform well for the money, but with new things on the horizon we are not sure if we can recommend them just yet.

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