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It may come as something of a surprise, being that its Phenom CPUs have been AMD's high-end chips ever since they launched at the start of 2008, but it's only with the launch of the Phenom II X4 965 BE that AMD has made its fastest ever CPU. Clocked at 3.4GHz, it finally surpasses the highest mark reached by its dual core sibling the Athlon 64 X2, which was released back in 2007 and ran at 3.2GHz (the recent 955 BE did equal this but not surpass it). Not that Intel is any different, its highest clocked chip was the single-core Pentium 4 570 that ran at 3.8GHz and was around back in 2004.
The point is, over the last few years the focus has been on getting better overall performance and this can be achieved far more easily through having multiple cores rather than having one faster core. Also, processor design has improved so that performance enhancements (even in single core parts) have come without clock speed increases. As such, it's taken us a number of years to get back to the point where raw clock speed is at the level it once was. That's enough of a history lesson for now, though. Let's crack on with the review proper.
The Phenom II X4 965 BE, then, is a quad core CPU built on the same architecture and manufacturing process as AMD's previous top dog, the 955 BE. At least that's how it appears from the outside. AMD has assured us that it has revised its manufacturing process slightly to allow such a fast processor to be produced. However, despite the CPU's name, this doesn't seem to have involved any black magic as the predominant reason AMD seems to have been able to achieve such a high clock speed is by increasing the default voltage of the CPU. The 955 BE used a reference voltage of 1.32V whereas the 965 BE has upped this to 1.4V. This might seem like a small change but it does mean the CPU's TDP has also risen from 125W to 140W.
This is all in stark contrast to Intel's impending Core i5 CPUs, which use a new architecture and employ new technology to allow better performance without increasing overall clock speed and thus power draw or heat output. Unfortunately, AMD's next generation of CPU designs aren't ready yet so it has had to keep trying to push clock speed up to remain competitive with Intel. Until Core i5 actually arrives, though, we can't say for certain which the better bet is.
Elsewhere the 965 BE's features are the same as we've seen on previous Phenom IIs so if you want the full low down on the architectural intricacies of the chip then check out our reviews of the Phenom II X4 810 and Phenom II X3 720 Black Edition as well as the Phenom II X4 940.
With so little to talk about in the way of features, the last thing to note before we move onto testing is that this CPU is a Black Edition. This refers to its unlocked multiplier which theoretically makes overclocking very easy. As we found with the 955 BE, though, adjusting the multiplier isn't the only way to effectively overclock a CPU and Intel's rival chips were able to keep up in the overclocking stakes by adjusting other parameters. We'll see how this chip fares in a moment.