AMD is delaying the release of large volumes of its Barcelona quad-cores until early next year because of a bug that could cause a system to crash, according to the Wall Street Journal.

The translation-lookaside buffer (TLB) bug also affects the just-released quad-core Phenoms and is a setback the company could do without at a time when rival Intel has regained the technological ascendancy.

AMD asked motherboard manufacturers to include a patch for the Bios of motherboards using the chips to bypass the problem. However AMD admits the patch slows systems down by 10 percent.

Intel's latest chips trounced Phenom systems in our lab tests, which appear to have been done on an unpatched system. The patch would in theory make them slower still but we plan to verify this.

Minor bugs in new chips are not unusual. A bug in Intel's very first Pentium caused a lot of embarrassment for the company, which was taken aback by the furore - one of the first to be stoked up by the burgeoning internet.

But some observers accuse AMD of rushing chips to market to prevent Intel pulling too far ahead.