In Nov. 2011, we discussed that TRIM support for RAID 0 was planned with the introduction of Intel's RST 11.5 drivers. Based on information listed in its 22.214.171.1249 Alpha release notes, Intel will be providing TRIM support with the final driver release;
"2. This release will not enable the TRIM on RAID0 feature, but it will be added in the next RST 11.5 release."
TRIM is a command that allows an operating system to inform a solid state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally, improving performance, but up until now this function was not available for a SSD in a RAID setup. During its introduction this past spring, the Intel 7-series chipset did not have TRIM enabled in RAID 0. This will change with a software upgrade.
With the Windows 8 right around the corner, news came out that TRIM support for RAID 0 will be dependent on running Windows 8 with an Intel 7-series chipset, along with the motherboard having RAID BIOS (Option ROM) version 11.5 or higher and Rapid Storage Technology (RST) device driver version 11.5 or higher.
This raised the question on whether or not TRIM is supported for RAID 0 on Windows 7 or does it required Windows 8 for the feature to be supported. We reached out to Intel for an official response on TRIM support for Windows 7 vs. Windows 8 in a RAID 0 setup. Intel provided the below response;
"Trim on RAID 0 for SSDs is supported in the Intel RST driver versions 11.0 and newer. Currently available for the general public on Intel’s downloads site is RST driver version 11.2 which offers TRIM support on RAID 0 compatible with MS Windows 7 OS on Intel 7 series chipsets (earlier chipsets NOT supported). Intel is also working on a future release providing support for TRIM on RAID 0 on Microsoft Windows 8 OS for Intel 7 series chipsets."
Based on Intel's response, it looks like it is officially supported on Windows 7 with RST driver version 11.2 and Intel 7-series chipsets. It looks like it is not "officially" supported on Windows 8 at this time.