Intel Core 2 Quad review

Intel's Core 2 Quad processors have four cores - twice as many as the Core 2 Duo and Pentium Dual Core chips - which makes them ideal for running multiple programs simultaneously.

Alternatively, multi-threaded programs, such as most video-editing packages, can put all four cores to work on a single task. This can produce impressive results in these programs, reducing processing times to a fraction of what was possible with a single-core processor.

A Core 2 Quad processor is essentially two Core 2 Duos stuck together on the same chip. Each half has its own L2 cache, which the two cores share. Unlike Intel's Core i7 processors and AMD's Phenom chips, these processors have no L3 cache shared between all four cores. This means these chips are likely to make more requests to the system memory. There's a large range and we've tested ten of them here.

Different ranges

The Q6000 series of processors have a Kentsfield core and were Intel's first desktop quad-core processors. They are the only quad-core processors that Intel still manufactures using a 65nm process, and have a quad-pumped external bus speed of 1,066MHz. Each pair of cores shares a 4,096KB L2 cache (8,192KB in total).

The newer Q8000, Q9000 and Q9050 series processors use a Yorkfield core, which is manufactured using a smaller 45nm process. This makes them cooler and more power efficient. They have a quicker 1,333MHz quad-pumped external bus speed, too. The Q8000-series processors have two 2,048KB L2 caches, while the Q9000 series have two 3,072KB L2 caches. The Q9050 series has two 6,144KB L2 caches - the largest we've seen.

Specific processors

The Core 2 Extreme QX9650 is the fastest Core 2 Quad processor here. Its Extreme branding means that its multiplier is unlocked, making it more flexible for overclockers who want to push it even further. However, at £737, it's simply too expensive for most people. The Core 2 Quad Q9650 performs similarly, but isn't multiplier unlocked. It's still very expensive at just over £400, though.

The best-value Core 2 Quad processor here is the 2.33GHz Q8200. It fared well in all our benchmarks and costs a reasonably low £149. It runs cooler than the similarly priced Q6600 and Q6700 processors, which have comparable performance. It's also better value than the Q8300, Q9300 and Q9400 processors, which are more expensive, but for little speed gain.

If you want an even faster quad-core Intel processor, we recommend the Q9550. It's noticeably quicker than the Q8200, it doesn't cost much more than the Q9450 and isn't nearly as expensive as the other processors here with higher clock speeds.