Unfortunately, little has changed since November. We tested Realtek's latest 1.66 audio drivers in Windows XP with an EVGA 122-CK-NF68 motherboard that features an ALC885 codec chip, and EAX occlusion and obstruction effects still aren't working. This problem is easily observed with RightMark 3D Sound 2.3, but it also affects games, including Battlefield 2. That title makes particularly extensive use of occlusion and obstruction effects, and it's still unplayable in EAX mode with Realtek's audio drivers.
Since Windows Vista doesn't support EAX, this isn't an issue for that operating system. However, those planning to use onboard audio with Windows XP would do well to avoid Realtek codecs if proper EAX support is a priority.