What makes a CPU 'extreme'? For the Intel Core 2 Duo Extreme Processor QX9770 it's a 3.2GHz clock speed, a 12MB level 2 cache and a 1600MHz front side bus. Why would you need such a fast and well equipped CPU? Mainly for video rendering and other applications that will benefit from a fast clock speed and multithreading. For the average computer user, who will be browsing the Web, playing the odd game and working on office and photo applications, this CPU is overkill.

The QX9770 is very similar to the QX9775 CPU, but it's aimed at professionals and enthusiasts who want the fastest four-core solution they can find. Indeed, both the QX9770 and QX9775 are quad-core CPUs and they share the same clock, cache and front side bus statistics. Both are built using Intel's 45nm (nanometre) technology, but the QX9770 is designed to work in a single-socket motherboard. It's still based on a 775-pin socket, whereas the QX9775 is based on a 771-pin socket and is designed to run in Intel's dual-CPU-based Desktop Board D5400XS (Skulltrail) motherboard.

Technologically, the 45nm manufacturing process is the smallest process in use from Intel for its CPUs and is currently smaller than AMD's competing Phenom offerings, which are built using 65nm technology. This means that the QX9770 has room for more, smaller transistors – it packs over 800 million of them, in fact. The Q9770's core is essentially two dual-core CPUs in the same physical package and each dual-core portion of the CPU has its own 6MB level 2 cache.

To measure its performance, we used an ASUS Rampage Formula motherboard, which is based on the Intel X48 chipset, along with 2GB of 1066MHz DDR2 memory, a Seagate Barracuda ES hard drive and an ATI Radeon HD 3450 graphics card. In WorldBench 6, the CPU scored 127, which is a very competitive figure, but it was in the Blender 3D test where we found its performance to be identical to the QX9775.

Rendering a project using one thread, the QX9770 took one minute 45 seconds. Using two threads it took 55sec and four threads to 29sec. These results are identical to the QX9775, which we tested in the Skulltrail kit. It's not surprising though, as both CPUs have the same specifications. The 3.2GHz frequency is actually the fastest of the current crop of Core 2 CPUs and this speed is attributed to the faster front side bus speed of 1600MHz, which also means the CPU can interact with the memory at a faster rate than CPUs with a slower front side bus. Of course, we used DDR2 memory running at 1066MHz, but a motherboard with DDR3 memory running at a native 1600MHz speed should yield even faster results.

But if you're thinking about getting the QX9770 for your latest high-end machine, you'll have to make sure your motherboard's chipset supports it. While a motherboard with an Intel X48 chipset is sure to support it, boards based on the X38 might also be able to run it. As always, it's best to check on your motherboard manufacturer's Web site to make sure.

As for heat and power consumption, the QX9770 has a TDP (thermal design point) of 135W, but this is actually a competitive figure for a quad-core CPU, thanks to the 45nm manufacturing process. It beats AMD's fastest Phenom CPU – the 9900 – which is based on a 65nm process and approximately half as many transistors (over 400 million) for its TDP rating of 140W. Still, you'll need a decent heat sink and fan assembly to keep the QX9770 running cool, and a hefty power supply will be required, too (think over 500W, depending on the configuration of your machine).