I bought a brand new Macbook Pro, 15″, one of the mid 2009 models.  I’m using the 7200 RPM hard drive I bought for my 13″ Macbook, so I already had Windows 7 installed.

Everything works great except I had issues with the audio.  The Macbook, as well as I presume the 2008 Macbook Pros, used a Realtek audio chip.  I installed and reinstalled several versions of the Realtek High Definition Audio drivers from their website on my new Macbook Pro and had no luck.  If you go searching for solutions for this you mostly get people telling you to reinstall Realtek drivers, use “RealtekSetup.exe” from the Leopard install DVD, and so on.  I began to wonder if Apple switched audio chip suppliers, so I started looking at the PCI device.

The PCI ID for the sound chip has vendor id 1014 which comes up as Cirrus Logic.  I then went looking on the Mac OS X Leopard install DVD which has a folder for Boot Camp drivers.  There’s an Audio directory and what do you know, there’s a driver called “CirrusVista64.exe”.  That turned out to be the right driver; I now have a Cirrus Logic CS4206A sound chip in Device Manager.

So apparently Apple has switched sound chips in the 2009 Macbook Pros.  I haven’t seen this ANYWHERE so hopefully this helps out anyone else in my situation.  Now if they’d only fix the trackpad issues…

edit (5 Sept 2009): Since I posted this, new Boot Camp drivers (version 3.0) have been released with Snow Leopard, which have fixed any issues I’ve encountered under Windows XP and Windows 7 (32 and 64 bit).  Even right-click on the trackpad is working.