Abit BH7

When it comes to overclocking, not all motherboards are created equal. Some don't give you any options for overclocking, while others, such as Abit's BH7, are designed for this purpose alone. Abit has been designing motherboards for enthusiasts for a number of years and some may remember the legendary BH6, which was based on Intel's 440BX chipset. It has taken a while, but Abit has finally released a successor, based on the much more recent Intel 845PE chipset.

It's relatively new, but the 845PE is already looking dated next to the new 875P chipset, lacking a dual-channel memory controller and even AGP 8x. However, it's also a proven performer and, coupled with Abit's engineering know-how, it's a fine candidate for maximum tweakability.

In addition to the basic features of the 845PE chipset, Abit has added a few extras, including a Serial ATA bridge supporting a single Serial ATA device. There's also a LAN and six-channel audio via the ubiquitous Realtek ALC650, but Abit takes audio a stage further by including a 24-bit optical in and out on the backplane. The remaining ports are all fairly standard, although Abit doesn't provide a backplate to take advantage of the two free USB 2 headers, limiting you initially to the four provided on the backplane.

But the BH7 leaps ahead of most other Pentium 4 boards with its BIOS options. Abit's SoftMenu provides an enormous amount of control and is geared towards the extreme overclocker. FSB speeds can be adjusted in 1MHz increments up to 250MHz (effectively 1GHz), even going beyond the requirements for the new Pentium 4 CPUs with an 800MHz FSB.

Abit also provides plenty of flexibility for AGP/PCI speeds, offering a number of set clock dividers and fixed values. DDR memory speeds are set by ratios of 1:1 or 3:4 based on a 400MHz FSB; and 1:1 or 4:5 based on a 533MHz FSB.

Voltage adjustments are impressive too, allowing for DDR DIMM voltages of up to 3.05V, 1.6V for the AGP port, and boosts of up to 30 per cent for the CPU voltage. You'll need some serious cooling to run at the higher settings, and you're probably best advised to err on the side of caution.

Memory timings are adjustable too, and there's even an option to run with an extra-low CAS latency of 1.5, providing your memory is up to the job.

Unless you're lucky enough to have an unlocked engineering sample, your overclocking exploits are going to be limited by your CPU's fixed multiplier. We experimented using our massive Thermaltake Spark 7 cooler (from www.chillblast.com) and a 2GHz Pentium 4, which, after a bit of trial and error, ran happily at 2.6GHz, with a 173MHz FSB. However, it was our little 2.2GHz Celeron that took the accolades, running rock-solid at 3.46GHz with the DDR memory running at 420MHz. The performance boost was fantastic, increasing our 3DMark2001 SE score by nearly 50 per cent.

The BH7 may not be based on cutting-edge technology, but it's still a great performer, and there's no doubting it's one of the best boards you can buy if overclocking is your game.

Author: Gareth Ogden