If you're in the market for a new high-end PC, it's worth spending your cash on a platform based on the Core i7. This Extreme Edition CPU will also let you overclock it reliably, and allow you to get close to 4GHz while only using an air cooler.

It's not going to get AMD any new users, but existing AMD platform users might benefit from the extra upgrade option. On its own, the tri-core Phenom X3 8750 is a fast CPU, but when its street price is compared against Intel's Core 2 Quad 6600 CPU, it doesn't look good at all.

The Core 2 Extreme QX9770 is for demanding users who want the current fastest quad-core performance on the market.

Its performance isn't stellar, but it doesn't consume much power and it runs almost silently. This makes the 4850e desirable for a media centre, or any PC where noise and heat issues need to be tackled.

It's worth considering the Phenom 9900 if you want to extract top performance out of your existing AMD-based system, but the upgrade path might not be a smooth one. Wait until the motherboard manufacturers iron out any BIOS issues before investing in it.

Those of you who already own an AM2-based AMD motherboard can give your PCs some added punch by upgrading to a Phenom 9600 quad-core chip. Sure, it's not as fast as an Intel Core 2-based CPU, but it's still a very decent product, which also has plenty of features that aim to reduce power consumption during idle times.

As usual there's a hefty price on this right now, but the new transistor technology and larger cache seem to have given this CPU a nice boost over its predecessor. If you want the extra speed and would also like to do some overclocking it's worth considering.

Users already using an AMD platform may want to consider an upgrade to Barcelona, but it remains to be seen if AMD will win over any new users.

It's bound to be expensive, but users who are out to build the fastest rig on the block will appreciate the extra speed

With a default speed of 2.93GHz, this is currently the fastest desktop quad-core CPU on the market. At its default speed, the QX6800 didn't perform much faster than the QX6700, but we were able to overclock it reliably up to 3.47GHz, where we observed much better gains in performance. It's definitely a high-end CPU for a professional, a gamer or an enthusiast user, and it has a high-end price tag to match.

The Core 2 Duo is currently the fastest mainstream CPU family on the market and is perfect for most scenarios. Even the slowest Core 2 Duo will provide excellent performance for gaming, everyday computing, video editing, MP3 encoding and heavy multitasking.

Core 2 Extreme CPUs are aimed at the high-end of the personal computing market. They are a suitable fit for expensive gaming PCs and are great for video editing rigs and for those of you who use design applications and want to build an entry-level workstation, rather than a more expensive one based on Intel Xeon CPUs.