Advanced Micro Devices today said it has delayed volume shipments of its quad-core Opteron processors as it fine-tunes the chip. AMD located one bug on the L3 cache of the chip that caused system problems, said Phil Hughes, an AMD spokesman. There are a number of fixes to this problem, including a BIOS fix that AMD has issued, Hughes said. AMD is working with partners to fine-tune the chip to ready it for mass shipment in the first quarter of 2008. The quad-core Opteron, also called Barcelona, is shipping in limited quantities to customers running high-performance computers, Hughes said. The delay will affect AMD, which has already lost ground in the server chip market to Intel Corp. in recent quarters. After months of delays, AMD released the Barcelona processor in September. Intel also took a step ahead of AMD when it launched the 45-nm quad-core Penryn processors last month. AMD still manufactures chips using the 65-nm process.