Now with the potential for some decent overclocking action, the Phenom II X4 processors represent a much better value than the originals ever were. However, it's unfortunate to see that the 20% clock frequency increase didn't make the Phenom II X4 940 significantly faster in many of the real-world tests we threw at it, and there are a few possible reasons for that.
Unlike the Core 2 Duo processors that are overclocked by increasing the FSB - effectively raising the frequency of both the processor and memory - the Phenom II X4 940 Black Edition is best overclocked using the clock multiplier.
The Phenom II processors are still intolerable to FSB injections, and increasing the bus will almost always create problems in achieving a decent stable overclock. While it's very easy to throw a 400MHz FSB at Core 2 processors, this is simply not the case with the Phenom II X4. That's also why purchasing a Black Edition processor becomes a must for those planning on carrying out a little overclocking.
As shown in our tests, your mileage will vary from 5-20% boost in performance which is very decent. But the most disappointing part came when we learned the effect this would cause in power consumption with ~50% more power whether at idle or under load, you can throw the Phenom II's excellent operating efficiency out the window.
As things stand today, even with the improved overclocking abilities of the Phenom II X4, these processors are better used for building a low cost quad-core enabled system or as powerful yet relatively cheap upgrade solution for existing AM2+ systems. For the ultimate in performance, however, it is hard to go past the Core 2 Quad series, let alone the new Core i7.
Bonus feature: Not your standard overclock...
During CES 2009 AMD showed the Phenom II X4 running at a staggering 6.5GHz (!!) using a combination of liquid nitrogen and liquid helium to reach CPU temperatures of -232 degrees Celsius. Watch the video.