Microsoft is supporting the FireWire standard - backed by Apple - rather than USB 2.0 in the forthcoming release of its Windows XP operating system.

USB 2.0 and FireWire connect PCs to peripherals such as hard drives. FireWire is used a lot in digital-video transfers. USB 2.0 delivers a throughput of up to 480Mb per second (Mbps) versus FireWire's 400Mbps -this translates to 60MB per second (MBps) and 50MBps respectively.

Both Apple and Sony offer FireWire on every PC or notebook they sell. USB also has a large user base - USB 1.1 is built into 99 per cent of PCs sold - but its inferior speed has reduced it to hooking up low-band peripherals.

Shock support Microsoft's support for FireWire has come as a surprise to many analysts, as the former joined Compaq, Hewlett-Packard, Intel and Lucent Technologies as a founding member of the USB Implementers Forum.

Microsoft said: "USB 2.0 support will not be included in the final version of Windows XP, due to the fact that there is not a sufficient array of production-quality devices to test against," claims

Dataquest analyst Martin Reynolds said: "Microsoft will not ship support for a standard that they can't guarantee a great user experience on. So far, USB 2.0 looks good as a concept, but little else.

"We've had demonstrations of proof of concepts, but without a plethora of products out in the marketplace, it is difficult to gauge it. At this point, it doesn't make a lot of sense for Microsoft to put in a set of drivers that are not debugged and fully qualified."

Last week Microsoft also announced that it is not supporting Bluetooth, a wireless connectivity standard in Windows XP.