Shortly after the launch of the Intel Sandy Bridge processors and Cougar Point chipsets, FreeBSD 8 and other BSD operating systems were attempted to be run on the Sandy Bridge test systems, but it didn't go too far. The support wasn't there. With the release earlier this month of FreeBSD 9.0 Beta (and subsequently the PC-BSD 9.0 Beta using the same packages plus their usual BSD desktop optimizations), another shot was attempted.
FreeBSD 9.0 begins to switch over to the Clang/LLVM compiler rather than GCC, provides initial USB 3.0 support, initial TRIM support for Serial ATA SSDs, and has numerous other enhancements.
First when trying to boot the beta of FreeBSD/PC-BSD 9.0 on an Intel Sandy Bridge notebook, problems quickly came up of run_interrupt_driven_hooks: still waiting after XX seconds for xpt_config. Eventually, a kernel panic is generated when the run_interrupt_driven_config_hooks is waiting too long and the installer then just drops down to the KDB debugger. Fortunately, I've run into this problem long ago on FreeBSD. This waiting too long for xpt_config problem on boot is actually an IEEE-1394 Firewire problem.
The workaround to get the installer booted is actually to disable the Firewire support from the UEFI/BIOS, assuming your system allows you to disable the IEEE-1394 support from there. You'll be left without Firewire support in FreeBSD, but at least your system can boot.
With Firewire disabled, the Intel Sandy Bridge system quickly booted into the PC-BSD 9.0 Beta installer. After that, it was just a normal install process.
While FreeBSD 9.0 is bringing up USB 3.0 support, a key feature missing from the operating system is the Intel HD 3000 graphics support. Right now the really only usable form of graphics driver support is using the proprietary NVIDIA GeForce/Quadro driver on FreeBSD 32-bit/64-bit. FreeBSD doesn't yet have the full support for kernel mode-setting, GEM/TTM, and other areas of the open-source graphics stack that have since moved into the Linux kernel.
With Intel no longer providing user-space mode-setting support for their IGPs, there is no way to have the support until FreeBSD has a Linux-like KMS infrastructure in place and the Intel 965 driver ported. There is the effort under-way currently to do this: bringing GEM, DRI, and KMS to FreeBSD. FreeBSD is financing the work, which is focused on supporting the Intel driver and will include the SNB hardware. While there is working support as of the past few months, it's still far from finished and will not be ready or merged into FreeBSD 9.0.
Without any graphics support, unless you're planning to use a discrete NVIDIA graphics card for now or just using the Sandy Bridge hardware for a head-less server, it doesn't even make much sense to use BSD.
However, that's not the only problem. After the easy installation of PC-BSD 9.0 Beta and rebooting, there's UEFI boot problems and even when attempting to boot the PC-BSD installation in the legacy mode. The system couldn't boot to the 9.0 beta installation even in legacy mode and with AHCI or IDE modes. This issue is still being explored. There's certainly interest and some development work in UEFI support for FreeBSD (e.g. this thread), but that isn't as ready as Linux.
Stay tuned for more information.