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AMD Phenom X3 8750 Tri-Core Processor
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Date: Apr 23, 2008
Section:Processors
Author: Marco Chiappetta
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Introduction and Specifications


When AMD first announced plans to introduce triple-core processors back in September of last year, reaction to the news was mixed.  Some felt that AMD was simply planning to pass off partially functional Phenom X4 processors as triple-core products, making lemonade from lemons if you will.  Others thought it was a good way for AMD to increase bottom line profits, getting more usable die from a single silicon wafer and mitigating yield loss.  We were somewhat perplexed by the first reaction.  This is an age-old strategy in the semiconductor space and after all, the graphics guys have been selling GPUs with non-functional units for years.  AMD was simply borrowing a play from ATI's playbook.

If you take a step back and think about it though, who really cares outside of the enthusiast niche'?  Isn't it the ultimate quality of the end-product what's most important?  If tri-core processors end up outperforming competing dual-core chips, and are less expensive than quad-cores, wouldn't salvaging otherwise unusable die from a wafer be a good move on AMD's part?

Without actual product, it's tough to argue either way, of course.  But thankfully, AMD has delivered their first batch of triple-core processors and we can finally put the whole debate to rest.

 
AMD Phenom Retail Box

AMD Phenom X3 Processors 
Specifications and Features

Model / Processor Frequency: AMD Phenom Processor Model X3 8750, 8650, 8450 / 2.4GHz, 2.3GHz, 2.1GHz
L1 Cache Sizes: 64K of L1 instruction and 64K of L1 data cache per core (384KB total L1 per processor)
L2 Cache Sizes: 512KB of L2 data cache per core (1.5MB total L2 per processor)
L3 Cache Size: 2MB
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: 65nm (.065-micron) Silicon on Insulator (SOI)
Approximate Transistor count: approx. 450 million (65nm)
Approximate Die Size: 285 mm2 (65nm)
Nominal Voltage: 1.05-1.25 Volts
Max Ambient Case Temp: 70 degrees Celsius
Max TDP: 95 Watts
ACP: *to be announced after launch
Future Memory Controller Note: Future 45nm processors versions are planned to include support for DDR3 memory

   

AMD Phenom X3 8750

As you probaly expect, the new AMD Phenom X3 8750 looks exactly like any other socket AM2+ processor outfitted with AMD's standard heat spreader.  The chip also uses the same packaging and socket as current Phenom processors; it is only the silicon underneath that has changed.

The AMD Phenom X3 8750 is a 2.4GHz processor manufactured using AMD's 65nm Silicon on Insulator process technology.  The chip has a Max TDP of 95W and has official support for a 1.8GHz memory controller and HT 3.0 frequency with Dual Dynamic Power Management technology.  Although some AMD processors have support for a 2GHz memory controller and HT3.0 link frequency, not every CPU is rated for these high-end frequencies.  Also note the "50" in the processor's model number.  That "50" means the CPU is based on the recently released B3 revision to the Phenom core which does not suffer from the infamous TLB errata.

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Vital Signs and Overclocking



As we've already mentioned, AMD’s new Phenom X3 8750 processor look just like all current Phenom processors.  It utilizes the same packaging and pin configuration.  But underneath its heat-spreader lies a CPU die that has one of its execution cores disabled.


  
Details from CPU-Z with the Phenom X3 8750

 

The latest version of CPU-Z correctly identifies and outlines the Phenom X3 8750's inner workings.  As you can see, the processor is based on the Toliman core with socket AM2+ packaging.  It is clocked at 2.4GHz (12 x 200MHz) and our particular chip is stepping "DR-B3".  As you can see, the chip also supports all of the instructions sets listed in the aptly named "instructions" section.  The processor’s 1.5MB L2 cache configuration (512KB per core) is 16-way set associative, but the processor's 2MB of shared L3-cache is 32-way set associative.  Please note, that because one of the execution cores is disabled on the X3 it has 512K less total L2 cache versus a Phenom X4 and 128K less L1.

Overclocking The Phenom X3 8750
Tri-Core Flat-Out

We know many of you are wondering just how much clock speed headroom the Phenom X3 8750 has left under the hood, so we spent some time overclocking our chip using a Gigabyte 790FX-chipset based motherboard.  Because the Phenom X3 8750 is not a "Black Edition" processor, its multiplier cannot be increased for overclocking.  That meant we could only overclock by altering the HT frequency, but we still had some pretty good luck.





Phenom X3 8750 Overclocked to 3.0GHz


By altering the HT link multiplier, memory controller multiplier, and the HT link speed, and increasing the CPU voltage to 1.45v, we were able to take our Phenom X3 8750 to a cool 3.0GHz using nothing but a stock AMD PIB cooler.  Higher frequencies were possible, but we couldn't keep the system 100% stable, so we backed things down to 3.0GHz.  While running at that speed, we re-ran some tests and also monitored core temperatures and found that the chip never broke the 45ºC mark - at least according to AMD's Overdrive software.  That is one heck of an overclock and some pretty cool temperatures for a Phenom in our opinion.  If the majority of chips have the same amount of headroom as ours, we suspect these tri-cores will be mighty appealing to AMD enthusiasts on a budget.

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Our Test Systems and 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:
Core 2 Extreme QX9650
(3.0GHz - Quad-Core)
Core 2 Quad Q6600
(2.40GHz - Quad-Core)
Core 2 Duo E6850
(3.0GHz - Dual-Core)
Core 2 Duo E6600
(2.40GHz - Dual-Core) 

Asus P5E3 Premium
(X48 Chipset)

2x1GB Corsair DDR3-1800
CL 7-7-7-20 - DDR3-1333

GeForce 8800 GTX
On-Board Ethernet
On-board Audio

WD740 "Raptor" HD
10,000 RPM SATA

Windows Vista Ultimate
NVIDIA Forceware v163.75
DirectX Redist (November 2007)

System 2:
AMD Phenom X3 8750
(2.4GHz)
AMD Phenom X4 9850
(2.5GHz)
AMD Phenom 9600
(2.3GHz)
AMD Athlon 64 X2 3200+
(3.2GHz) 
AMD Athlon 64 X2 4600+
(2.4GHz) 

Gigabyte GA-MA790FX-DQ6
(AMD 790FX Chipset)

2x1GB Corsair PC2-8500
CL 5-5-5-15 - DDR2-1066

GeForce 8800 GTX
On-Board Ethernet
On-board Audio

WD740 "Raptor" HD
10,000 RPM SATA

Windows Vista Ultimate
NVIDIA Forceware v163.75
DirectX Redist (November 2007)

 

 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 X2 8750 processor (CPU Arithmetic, Multimedia, Multi-Core Efficiency, Memory Bandwidth, Cache and Memory Bandwidth and Memory Latency).  All of the scores reported below were taken with the processors running at its default clock speed of 2.4GHz, with 2GB of DDR2-1066 RAM running in 128-bit unganged mode.



Processor Arithmetic


Multimedia


Multi-Core Efficiency




Memory Bandwidth




Cache and Memory




Memory Latency



SiSoft SANDRA's various benchmark modules reported scores right in-line with logical expectations.  The tri-core chip was more powerful than AMD's dual-core offerings, but note quite as powerful as a quad-core.  The multi-core efficiency and various memory related tests all reported similar scores to quad-core Phenom X4 processors, which is to be expected considering they are the essentially identical.

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PCMark Vantage

We ran a handful of processors and platforms, including the new Phenom X3 8750, through Futuremark’s 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


With the exception of PCMark Vantage's "Memories" test, the Phenom X3 8750 performed exactly as expected.  In the "Memories" test, the Athlon 64 X2 6400+ finished slightly ahead of the 8750, but in all of the other tests the 8750 proved to be faster than any previous AMD dual-core chip, and right on par with the Core 2 Duos.  Of course, the quad-core chips were fastest overall, but the Phenom X3 8750 put up a strong showing and its encouraging to see that applications are properly taking advantage of the odd number of cores.

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LAME MT and KribiBench

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.

LAME MT
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.




LAME MT utilizes a maximum of only two threads, so considering the Phenom X3 8750's 2.4GHz clock speed, we expected it to finish ahead of the 2.3GHz Phenom X4 9600 but behind the Phenom X4 9850, and that's exactly what happened.


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 where 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.


The Phenom X3 8750 put up some interesting scores in the KribiBench tests.  As you can see, the chip was faster than any of the dual-cores including Intel's Core 2 Duo E6850 which is clocked 600MHz higher.  Only the quad-core chips were faster.

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Cinebench and 3DMark06

Cinebench R10 is an OpenGL 3D rendering performance test based on Cinema 4D. Cinema 4D from Maxon 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 time it took each test system to render the entire scene is represented in the graph below, listed in seconds.


The Phenom X3 8750 didn't perform quite as well in the Cinebench R10 benchmark as it did in Kribibench, but the results were fairly good nonetheless. In this test, the dual core Athlon 64 X2 6400+ was faster in the single-threaded test and the Core 2 Duo E6850 pulled ahead in both the single-and multi-threaded tests. 

Futuremark 3DMark06
Synthetic DirectX Gaming

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.


3DMark06's built-in CPU benchmark had the Phenom X3 8750 finishing well ahead of any of the dual-core processors we tested, but behind all of the quad-cores.  And once again, the non-symmetrical number of cores seems to have had no ill effects in any off the applications we've tested thus far.

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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





Our low-res gaming benchmarks tell essentially the same story we've seen throughout this article - the Phenom X3 8750 finished of all of the dual-core chips with the exception of the Core 2 Duo E6850 in the F.E.A.R. benchmark.  In Crysis though, the Athlon 64 X2 6400+ and E6600 were also able to pull ahead of the X3 8750.

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Total System Power Consumption


Before we bring this article to a close, we'd like to cover a few final data points. Throughout all of our benchmarking and testing, we monitored how much power our test systems were consuming using a power meter. Our goal was to give you all an idea as to how much power each configuration used while idling and 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 motherboards alone.

Total System Power Consumption
Tested at the Outlet



The Phenom X3 8750's power consumption characteristics are very interesting.  Despite having an extra core and outperforming the Athlon 64 X2 6400+ more often than not, the X3 8750 used less power than the dual-core chip while under load.  While idling though, the Phenom X3 8750 used somewhat more power than all of the other processors we tested, with the exception of the Phenom X3 9850.  And looking at the graph shows that Intel still has a huge lead in this area, thanks to the power efficiency of their entire platform.

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Our Summary and Conclusion



Performance Summary: Somewhat surprisingly, AMD's new Phenom X3 8750 performed exactly as a triple-core CPU should in our battery of benchmarks.  When the chips were first announced, we weren't sure how today's applications would react to a non-symmetrical multi-core processor, but all of the applications we tested behaved normally and simply took advantage of the additional processor resources.

Throughout  testing, the Phenom X3 8750 performed in-line with our expectations, outpacing the dual-core chips more often than not, and falling behind the quad-cores in all of the multi-threaded applications.  Despite a huge clock speed disadvantage, the Phenom X3 8750 was able to outpace the 3.0GHz Core 2 Duo E6850 in a handful of tests, and in all but a couple of tests it was faster than the 3.2GHz Athlon 64 X2 6400+ as well.





AMD's new Phenom X3 8750 puts AMD is in an interesting position.  Before we explain that, let's get some particulars out of the way...

 

As you can see, AMD is pricing the X3 8750 and its lower clocked siblings at $195 and below in lots of 1000. That makes the chip we tested here today about $5 cheaper than the lower-clocked, 2.2GHz quad-core Phenom X4 9550, $20 cheaper than the similarly clocked Phenom X4 9750, and about $30 more expensive than AMD's fastest dual-core chip, the Athlon 64 X2 6400+.  You'd expect the Phenom X3 8750 to be more affordable than AMD's current quad-core chips, but the prices are so close at the moment, there's no reason not to spend the extra 20 bucks for the extra core offered by the 9750 in our opinion, provided you've got a motherboard that can handle its 125W TDP.  In light of Intel's current offereings, the Phenom X3 8750 is about $30 and $95 less expensive than the Core 2 Quad Q6600 and Q9300, respectively, and right on par with the Core 2 Duo E6850 or E8400. So again, if you've got the budget, the additional investment required for a quad-core chip makes sense considering how much faster they are with the right application workload.

At under $200 though, we think the Phenom X3 8750 could appeal to two completely different audiences, and for two totally different reasons.  In the mainstream space, the Phenom X3 8750 could easily be used in a budget PC  when paired with an AMD 780G-based motherboard.  In that usage model, you could have an AMD triple-core with arguably the best IGP available to-date, versus an Intel dual-core with an inferior IGP.  If you're planning to build a PC and use integrated graphics, the Phenom X3s and 780G make a great combo.

Considering how well the Phenom X3 8750 overclocked, and the relatively low price of AMD 790FX-based motherboards and DDR2 memory, the X3 8750 should also appeal to modders on a budget.  In this space, the choice isn't as clear cut because Intel's recent price cuts and the excellent overclockability of its processors make them extremely attractive.  However, AMD's platform is significantly more compelling than it was just a few weeks ago, thanks to the release of B3 Phenoms and these new tri-core processors.

 


 

  • Good Value
  • Good Performance
  • Tri-Core "Just Worked"
  • Solid Overclocker
  • Ran Cool
  • Priced too close to similarly clocked AMD quad-core
  • Relatively high power consumption



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