Product Reviews

With all the excitement over dual-core processors, Intel's new, single-core high-end Pentium 4 range - the 6xx series - may seem like an odd move. However, where the dual-core parts will require new chipsets, the Pentium 4 660 runs on standard 915 and 925X Express motherboards.

Features-wise, top of the list is 64-bit support via the EM64T instruction extensions. Though not directly compatible with AMD's approach, the key point is support for the soon-to-be released 64-bit version of Windows XP.

Of more practical benefit are the power-saving features built into the new core. The 6xx series all include Enhanced SpeedStep, as featured in Intel's notebook parts. This throttles back frequency and voltage according to load,

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reducing power consumption. It doesn't mean you can use a smaller heatsink, since power dissipation at 100 per cent CPU load is still the same, but you can expect lower temperatures in normal operation, allowing the heatsink fan to spin slowly and reducing noise.

Lastly, although it's been supported since the 5xx series, Intel is making more of the 6xx series' support for the hardware XD (execute disable) bit, known in AMD land as NX (no-execute) bit, and in Microsoft land as DEP (data execution prevention). This is designed to prevent buffer-overrun hacker attacks in conjunction with Windows XP SP 2.

Despite its top-of-the-range status, the clock speed of the new part is lower than that of the previous P4 flagship, the Pentium 4 570. The top-end 660 runs at 3.6GHz to the 570's 3.8GHz. Instead, the 660 has twice the Level 2 cache of the 570, with a full 2MB.

The extra cache helped the 660 achieve an overall score identical to the 3.8GHz 570, despite the clock-speed deficit. The results breakdowns are different though: the 660 is slower at media encoding, but faster when managing operations on large datasets, such as our Excel tests.

A significant point release then, and we applaud many of the new features. However, it only makes us hungrier for the arrival of dual-core on the desktop.