What's has the same width as four tennis balls and is a tall as said spheroid? IBM's new ultra-compact desktop, the ThinkCentre S50, which was launched into the space-conscious Japanese market today.

The wee machine - not, it has to be said, the world's smallest PC - measures just 27.6 x 27.3 x 8.9cm, footprint that's 92 per cent of an A4-sized notebook, IBM said.

Despite the small size, the manufacturer provides a 3.2GHz 'Prescott' Pentium 4, though not in its Socket T form. Still, IBM reckons the units "rectilinear" cooling system, which pulls air in at the front, over the CPU, etc. and out of the back, is sufficient to keep the machine from overheating.

The S50 is based on an i865GV chipset with integrated graphics. There's 1GB of DDR SDRAM in there too, a DVD drive and an 80GB hard disk. Six USB 2.0 ports, legacy connectors and Gigabit Ethernet are among the I/O devices included, but expansion is limited to a single PCI slot.

IBM Japan said it will offer an alternative configuration based on a 2.53GHz Celeron D 325 processor, 256MB of RAM and a CD-ROM drive, all for ¥113,400 ($1030/£573). The P4-based version will retail for ¥212,100 ($1926/£1072).

Both models are due to ship next Monday, 30 August. ®

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