 Windows 7's AHCI enables not only NCQ but also TRIM support on SSD drives (with their supporting firmware).Older operating systems such as Windows XP require the installation of a vendor-specific driver (similar to installing a RAID or SCSI controller) even if AHCI is present on the host bus adapter, which makes initial setup more tedious and conversions of existing installations relatively difficult as most controllers cannot operate their ports in mixed AHCI–SATA/IDE/legacy mode.A 2004 test with the first-generation NCQ drive (Seagate 7200.7 NCQ) found that while NCQ increased IOMeter performance, desktop application performance actually decreased.