U-Power - a boutique PC manufacturer from Korea - is set to release an accelerator designed for the Power Macintosh G4 Cube. Unlike previous upgrades the PCube doesn't contain a G4 - or indeed any other PowerPC Chip - but brings Pentium-M power to Apple's venerable Cube.

U-Power's US spokesman Rudy Keppelmeyer explains that the PCube upgrade is designed not for conventional Mac users, instead aims for those PC users who admire the G4 Cube's design but don't want to run PowerPC software such as Mac OS, Mac OS X or Linux.

"There are a substantial number of people who love Apple's hardware from a design point of view, but who have no desire to run Apple software," says Keppelmeyer. "This upgrade is theirs. For people out of the ordinary."

The upgrade is based on the powerful mobile version of Intel's Pentium, the Pentium-M, and initial boards will be available in either 1.5 or 1.8GHz versions with 2MB L2 cache, manufactured on Intel's 90nm process.

Keppelmeyer explains that the innovative new upgrade is more than just a processor card. "There's a substantial difference between a G4 processor card and one with a Pentium onboard, and we've put the hard work in to ensure Windows compatibility."

"Not the least of our problems was working around the Cube's open firmware, the Mac equivalent if you like to a PC's BIOS. We have glue logic sitting in a layer over the top of open firmware allowing the real BIOS to believe it's interacting directly with the hardware" says Keppelmeyer. "Combined with a small layer of emulation to allow the execution of open firmware code, any software that runs on the PCube upgrade believes it's running on a PC with the same specifications as a Macintosh Cube".

Performance is expected to be slightly below the level of a similarly equipped PC, as the PCube cards must operate with the Cube's dated 133MHz memory bus. U-Power is already working on a solution, claiming an upcoming replacement daughterboard for the Cube will allow it to use faster DDR memory, faster wireless and other features using Intel's Centrino chipset.

"We don't believe this will be an issue with our target market, people who will finally have the Cube they've desired and be able to run their favorite software with it."

The PCube 1.5 and PCube 1.8 upgrades are compatible with Microsoft Windows XP Home, Windows XP Professional and Windows Server 2003, when used with the U-Power supplied drivers that allow Windows full access to the Cube's hardware.

Both upgrades will be available early next month, priced at $US399 and $US449 respectively. A 2.13GHz version is planned by late Summer.