In a hurry to build my Dynamics AX development server, I ordered an AMD Sempron 140 from Amazon.com earlier this year.  The AMD 1090T x6 Black Thurban processor was on back order at this time so many people had to settle for a cost effective alternative while they waited for the stock to come in.  The Sempron 140 processor soon showed its true worth as I enabled its hidden second core and SQL Server was happily churning away data with it.  The following review was written to show all the possibilities of this product and help you achieve the most for your hard earned dollar.

How does the Sempron 140 compare to the AMD 1090T x6 Black Edition processor?

How can you unlock the secret second core of the AMD Sempron 140?

Read On To Find Out!

Simply put, the AMD Sempron 140 only has a total of 128Kb Level 1 and 1Mb of Level 2 cache.  The AMD product runs at 2.7 Ghz and is Hypertransport 3.0 compatible.  In its stock configuration, I can only recommend this product for light duty use like web browsing because the single core can get overloaded quickly while playing games or watching movies. 

Unlocking The Second Core Of The AMD Sempron 140
Strange as it may sound, motherboard and CPU manufacturers are now giving us the ability to unlock unused processor cores for free. Technically, we enthusiasts and geeks have been doing this since early 2008 but those first motherboards were specialized enthusiast systems and their abilities could not be easily reproduced on a home computer system. Now, ASUS is offering these abilities on its AMD 890GX series of motherboards with much more consistent results.

To unlock my Sempron 140, I used the ASUS M4A89GTD PRO Motherboard which uses the AMD 890GX chipset.  There are two ways of unlocking those precious, hidden, CPU Cores with this motherboard: the ASUS Core Unlocker in the bios or a physical Core Unlocker switch. For the hands on type of tweaker, you can simply flip a switch on your motherboard called Core Unlocker or CORE_UNLOCKER in the instruction manual. To keep from opening the computer case, an adept BIOS tweaker can use the Advanced menu with the ASUS Core Unlocker setting. Either way, one simple reboot will tell you instantly whether your processor will unlock. Remember, the operation is dependent on the stability of the silicone on the die itself.  Not all of these AMD Sempron 140 processors will work but many people around the world are reporting success. 

Once you have unlocked the Sempron 140, CPUID reports it as the AMD Athlon II X2 440.  You will get two cpu cores and you should notice a performance boost immediately since the second cpu can help booting Windows 7 or Windows Vista 64bit.

Here is a list of motherboards that allow unlocking of the AMD Sempron 140 processor: M4A79T Deluxe, Crosshair III Formula, M4A79 Deluxe, M4A785-M, M4A77TD, M4A78L-M, M4N82 Deluxe, M4N78 PRO, M4N68T PRO, M4N75TD, M4A77TD PRO/U3S6


Heat Output And Recommended Motherboard Configurations
The die on the AMD Sempron 140 is manufactured at 45nm.  The small die size results in a reduction of thermal energy output by the processor itself.  With both cores unlocked on this processor, I was only able to register 116 degrees Fahrenheit with a full processing load on the stock AMD cooler.  With the Spire TherMax Eclipse II SP984B1-V2 universal CPU Cooler, I was able to reduce the resting temperature of the AMD Sempron 140 down to 75 degrees Fahrenheit.  

Benchmarks And Performance Discussion
For my benchmark setup, I used the ASUS M4A89GTD PRO Motherboard, a Corsair CMX8GX3M4A1600C9 XMS3 8 GB PC3-12800 Core i5 Memory Kit, Transcend VSeries 32Gb SSD SATA drive as the boot sector and a set of four Samsung 500 GB HD502HJ SATA II Hard Drives in a RAID 0 array with Windows Server 2003 Enterprise Edition as the operating system.

Super Pi V1.1 Results
Super Pi is an application that extrapolates the specified digits of PI into a text file. Using just one cpu core at time, the program has proven to be a very reliable stress test for many AMD and Intel products.  Processors with large on-die cache sizes and high memory bus speeds tend to do better in this benchmark.   A low processing time in this benchmark will directly translate to faster performance of web browsers so it is very important to pick a computer chip that excels in this test.

Here are the results of three runs at 1,000,000 digits of PI with the AMD Sempron 140 at Core Speed 2700 Mhz, Bus Speed 200 Mhz,  DRAM Frequency 669Mhz :
1)  27 seconds
2)  27 seconds
3)  28 seconds

Here are the results of three runs at 1,000,000 digits of PI at Core Speed 3521 Mhz, Bus Speed 260 Mhz with a dual core unlocked AMD Phenom 140 processor :
1) 23 seconds
2) 24 seconds
3) 23 seconds

In the same ASUS M4A89GTD PRO Motherboard, I later installed an AMD 1090T x6 Black Edition processor, 3.915 Ghz and a score of 18 seconds.

We can see that the real gains in computing power were realized with the increase in CPU Core Speed but I was also surprised to find that this only resulted in a 4 second savings. When compared to the performance of the mighty AMD 1090T running at 3.915 Ghz, we shave off an additional 5 seconds of processing time. The lack of Level 3 Cache on the AMD Sempron 140 processor is causing the system to have to execute more memory calls.  My conclusion is rather simple, if you want single threaded gaming performance then you are going to need to look for something besides the AMD Sempron 140 processor and its miniscule 1Mb of total cache.

Still the Sempron over powers anything of the previous generation Intel line up, the Intel Xeon 3.4Ghz 2Mb 800 FSB Socket 604 processor was only able to do complete this benchmark in 39 seconds.  The Intel 3.2Ghz 512Kb Pentium 4 was only able to do complete this benchmark in 1 minute 17 seconds.

POV-Ray 3.7 Beta Results
POV -Ray stresses the floating point unit and memory bandwidth of the processor to render stunning 2D images. A new version of the freeware 3D animation utility has been released that offers SSE2 enhanced processing extensions along with multicore optimizations that will utilize all the available cores in your computer.

Using the benchmark.pov file at 512x384 NO AA, I ran the following traces :
13 minutes 11 seconds; Core Speed 2700 Mhz, Bus Speed 200 Mhz, DRAM Frequency 669Mhz, Single core
6 minutes 1 seconds; Core Speed 3521 Mhz, Bus Speed 260 Mhz with a dual core unlocked AMD Sempron 140 processor.

In the same motherboard, I later installed an AMD 1090T x6 Black Edition processor and got these results :
3 minutes 24 seconds; Core Speed 3915 Mhz

The ability to stress a modern 45nm dual core processor was a real treat for me.  First, I was able to prove that dual cores alone will not double the processing power of your AMD motherboard.  The additional 821 Mhz (3521 - 2700 Mhz) showed that there was a some overhead associated with managing multiple cores on a processor.  Then, the mighty six core results told me that there was a mystical grey area in multi-threaded performance on these processors.  In fact, I have seen the similar results with Intel processors but only now have I been able to test both a single core and six core product in the same motherboard.  Sadly, the conclusion I drew from this was that the addition of eight core processors to the AMD product line is not going to directly translate into a 1 for 1 increase in computing power.  We will see a gain but more along the lines of a ratio closer to approximately .65 to 1.

You can clearly see the effect that activating the second core of the AMD Sempron 140 has by these benchmark results.   As a comparison, the AMD Athlon 4000+ Socket 939 processor was able to do complete this same POV Ray benchmark in 26 minutes 2 seconds.

AMD Sempron 140 Specifications
Manufacturer:  AMD
Model Number:  SDX140HBK13GQ
Code Name:  140
Product Name: AMD Sempron 140
Cpu Frequency:  2700Mhz
Physical Cpu Cores: 1
Inefficient Hyperthreading Cores:  0
Level 1 Cache Size: 64Kb code cache, 64Kb data cache
Level 2 Cache Size:  1 Mb
Manufacturing Die:  45 nm
64bit Operating System Support:  Yes
Memory Controller:  Integrated dual-channel DDR2/DDR3 Memory Controller
Instruction Sets Supported:  MMX, 3DNow!, SSE, SSE2, SSE3, SSE4a, Advanced Bit Manipulation, AMD64 technology, Enhanced Virus Protection, Dynamic Acceleration technology, Virtualization Technology
Warranty:  3 years parts and labor limited

Summary
I have long since removed this processor in favor of the faster AMD 1090T x6 Black Edition processor.  While it was installed, I had little problem with processing speed and could have used it indefinitely for all of my software development needs.  If you buy the right motherboard then the AMD Sempron 140 is arguably one of the best options for those seeking mid-level performance for their home or office computer.   The processor runs very cool, even with the stock AMD cooler and has been shown to be faster than any Socket 478 Pentium 4 available.  You can pick up this AMD product from most online retailers for less than $30 right now and even less if you wait for an auction on Ebay.com to complete.

In all I give the AMD Sempron 140 Socket 939 processor two thumbs up.

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