Overclocking Results:

stock max. oc processor speed: 3.1 ghz 3.795 ghz multiplier / bus speed: 15.5x 200mhz 16.5x 230mhz if you're new to Overclocking and not sure what to do, check out these two excellent Guides for some pointers: Overclocking the CPU and Memory Overclocking the Videocard

Like Intel's Extreme Edition processors, the AMD Black Edition CPUs are special because they ship from the fab multiplier unlocked. In other words, a Black Edition Phenom II X2 processor can be easily overclocked by increasing a value called the "CPU multiplier" from the stock setting, which in turn alters the equation that calculates overall speed of the processor.

The equation for the Phenom II X2 550 BE is (CPU Multiplier) X (Motherboard Bus Speed) = (Total CPU clock speed). Or mathematically; 15.5x 200MHz = 3.1GHz. So for example, altering the CPU multiplier to say 17x would result in this equation (17x 200MHz) and an overclocked CPU speed of = 3.4GHz. Get it?

Now in the light of the fantastic 1GHz overclock PCSTATS achieved with AMD's Phenom II X4 955 BE processor, I think it's safe to say we can push this dual-core Phenom II X2 550 BE at least that far... if not further. Overclockers ready? Start your engines.... Go!

First thing's first, I set the dual channel Corsair XMS3-1600C9 memory in the Gigabyte GA-MA790FXT-UD5P motherboard to run in DDR3-800 MHz mode. This way the memory won't hold the CPU back. A standard K8-series AVC Z7U7414001 heatsink was used for PCSTATS overclocking tests.

Overclocking is always luck of the draw, but with good components like the Gigabyte GA-MA790FXT-UD5P motherboard, a smooth 750W PC Power and Cooling power supply and high speed Corsair XMS3-1600C9 DDR3 memory, the system certainly is geared for a good race.

Overclocking by CPU Multiplier

Starting with the CPU multiplier first, which is set at 15.5x by default, PCSTATS quickly overclocked the Phenom II X2 550 BE processor by changing this to 16x, 17x, 18x and 18.5x without problem.

The Phenom II X2 550, just like its quad-core X4 955BE brother, overclocked nicely until a 19x multiplier was selected and the system promptly refused to POST.

Overclocking by Motherboard Bus Speed

Having reset the multiplier back to 15.5x, PCSTATS set about overclocking the dual-core Phenom II X2 chip by bus speed alone. To make a long story short, the Phenom II X2 would POST as high as 250MHz, but wouldn't load Windows Vista until this speed was dropped down to 240MHz. The end result was a bus speed overclock of 240MHz, yielding an overclocked result of 3.72GHz.

An overclock of 620MHz is good, but the Phenom II X2 can be pushed faster!

For PCSTATS' final round of overclocking tests the motherboard bus speed and CPU multiplier were reset, and we went about overclocking both towards the 240MHz mark and 18.5x level respectively. It wasn't long before the Gigabyte MA790FXT motherboard was back running at 230MHz, and the multiplier was up to 16.5x. To get there, PCSTATS had to increase voltages as follows: CPU vCore from 1.3V to 1.425V, DDR3 voltage up by 0.15V to 1.85V, and CPU NB up by 0.1V.

After a while trying out different combinations of bus speed and multiplier values, PCSTATS settled on overclock of 16.5x multiplier, 230MHz bus speed - a resulting CPU speed pushed to 3.795GHz - not bad at all!

Core-by-Core Power Consumption Tests

AMD's latest Phenom II CPUs are built on a 45nm manufacturing process, so we'll see if this, along with the re-architecting of the Phenom II's microprocessor design will reduce power draw compared to Intel's CPUs, as well as previous AMD chips.

As always, before any power measurements are taken the CPU power saving and clock speed throttling technologies like Cool 'n' Quiet, EIST (speedstep) and C1E power states are disabled. PCSTATS then set about stressing each core of the processor one by one, until all cores were loaded. For this we used Stress Prime (SP2004). The total system power consumption, measured in Watts, is monitored with an Extech Power Analyzer Datalogger (model 380803). The power meter is located between the main 120AC supply and the PC's power supply so it measures the entire computer system, the difference between CPU loaded and unloaded states is the key value to pay attention to.

Total System Idle Power Draw
Processor	Total System Power Draw
Intel Pentium 4 540	150 Watts
Intel Pentium D 840	165 Watts
Intel Pentium D 940	168 Watts
Intel Core 2 Duo E6600	117 Watts
Intel Core 2 Duo E6750	123 Watts
Intel Core 2 Duo E8400	131 Watts
Intel Core i7 920	144 Watts
AMD Sempron 3600+	120 Watts
AMD Athlon64 4000+	163 Watts
AMD Athlon64 FX-60	127 Watts
AMD Athlon64 X2 4800+	143 Watts
AMD Athlon64 X2 5000+	156 Watts
AMD Athlon64 FX-62	168 Watts
AMD Phenom II X2 550 BE	145 Watts
AMD Phenom II X3 720	155 Watts
AMD Phenom II X4 955 BE	148 Watts