Verdict: It's a Core 2 in disguise.

Although the Core 2 brand has undoubtedly been a great success for Intel, it's arguable that after more than ten years of multi-billion dollar advertising, the Pentium brand is far more recognisable, especially among non-PC enthusiasts.

For this reason, Intel's cheapest dual-core chips are branded as Pentiums, even though they're based on the same Conroe core as the Core 2 Duo. There are currently three models in the Pentium E2100-series: the E2180, clocked at 2GHz; the E2160, clocked at 1.8GHz; and the E2140, which runs at 1.6GHz. Each model has two cores that share a combined 1MB Level 2 cache and access the Northbridge through an 800MHz effective FSB. Due to their low frequency and small Level 2 cache, the Pentium E21-series CPUs are extremely energy-efficient. For example, when our test system was fitted with an E2160, it drew just 164W from the mains compared to 230W for a similarly performing Athlon 64 X2 system. Despite their budget pretensions, the Pentium E2100-series CPUs support 64-bit instructions, SpeedStep, Execute Disable and SSE3.

In most types of applications, there's very little perceivable performance difference between an identically clocked Pentium E2100-series CPU and a fully-fledged Core 2 Duo.

However, the tiny Level 2 cache severely hampers performance when you try to run more than more application at the same time, and also when gaming - the minimum frame rate in Crysis was affected by as much as 27 per cent.

Although the Pentium E2100-series CPUs are nearly half the price of the cheapest Core 2 Duos, due to AMD's massive price cuts, they don't look good against the super-cheap Athlon 64 X2 4000+, 4200+ and 4400+, which are slightly faster and cost a similar amount.

However, in our experience, even the Pentium E2140 can be overclocked to 3GHz with a standard HSF, while the E2160 and E2180 can be pushed further still. Once overclocked, the Pentium E2100-series CPUs leave the Athlon 64 X2 chips bobbing in their wake, so they're clearly the better buy, unless you're afraid to overclock your PC.

• 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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• Zerotherm Hurricane HC92-Cu 8800 - Other cooling hardware