Verdict: The Celeron 420 is the cheapest CPU ever made.

Intel has always used the Celeron brand for super-low-cost processors for business PCs. However, due to the bitter price war going on between Intel and AMD at the moment, even we were shocked by how cheaply you can now buy a Celeron. You can get hold of one for just £22 - less than the price of a newly released game such as Crysis or Call of Duty 4.

The last generation of low-cost Intel processors were branded as Celeron-D, and used a cut-down version of the Cedar Mill core, which was based on the NetBurst architecture.

However, the newly released Celerons are based on the Core architecture, so they're much faster and far more power-efficient. For example, the Celeron-D 356 from last year's CPU megatest took 43.328 seconds to run the SuperPi 1M test, the only benchmark we used in both Labs tests, while the Celeron 440 took 35.661 seconds. Although the Celeron series is based on the same Conroe core as the Core 2 Duo and Pentium E21-series, the Celeron CPUs only have a single core and a tiny 512KB of Level 2 cache.

As a result, although all the modern Celerons are considerably faster than the older Celeron-Ds, they're still woefully underpowered for running CPU-intensive tasks such as video encoding or gaming. In addition, as they have only a single core, they're absolutely hopeless at Folding@home, so despite their super-low price, there wouldn't be any point in building a massive farm of low-cost PCs using Celerons.

Worse still, the top-end Celeron 440 is the same price as a far faster dual-core Athlon 64 X2 3800+, meaning that the only Celeron worth considering is the super-cheap £22.90 Celeron 420, and only then if you really can't afford anything better.

• PSUs - 14th July 2008
• Multi-GPU graphics - 20th June 2008
• CPU water cooling - 17th June 2008
• Hard disks - 20th March 2008
• Audio hardware - 29th February 2008
• Graphics cards - 24th January 2008
• CPUs - 21st December 2007

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