On Wednesday, Creative forum administrator Catherina Karskens posted a lengthy update on the company's position and findings regarding the compatibility issues. Karskens says testing with "a large number" of systems and system integrators indeed yielded popping and crackling in some high-end gaming systems.
We believe that the larger volume of data being requested is, in some systems, causing larger access delays to system memory, especially when Sound Blaster X-Fi is sharing memory access with high-end graphics and/or hard drives. We have found that with certain high-end systems and configurations, Sound Blaster X-Fi is being held off from receiving data from the PCI bus for significant periods of time, in some cases for close to two-thirds of a millisecond. This causes our audio buffers to underflow, which produces crackling sounds. The obvious answer to this would be to increase the latency tolerance, but due to the requirement for audio to synchronize accurately with graphics, we cannot increase the latency tolerance beyond a certain point.Karskens adds that the problems can often be fixed by a simple BIOS update in some instances, and by setting system memory to run in dual-channel mode in others. Allegedly, running memory in single-channel mode by using fewer than two memory modules or arranging them incorrectly in the motherboard's DIMM slots results in popping and crackling when the X-Fi is combined with some motherboards. Affected users are advised to check their motherboard manuals to ensure memory is in fact running in dual-channel mode. Despite these findings, however, the company believes there "may be some other system-related issues that may continue to cause these symptoms for some remaining customers." Creative is working with major motherboard and chipset manufacturers to sort out these remaining problems, and Karskens says the company will report back "in the next 2 weeks." Thanks to reader SH SOTN for the tip.