As a RAID_1 (Mirror) configuration is typically used for greater reliability, the bulk of tests focused more on this aspect, rather than speed. Still, speed is evaluated briefly in this page, to gauge if performance is severely affected by redundant ops implemented under a Mirrored setup.
Sisoft Sandra 2000
Sisoft Sandra scores using NTFS drives (ATA-100 Mirrored)
Sisoft Sandra scores using FAT32 drives (ATA-100 Mirrored)
Remarkably, the mirrored drive scores demonstrates even better performance than a single ATA-100 variant. From our previous scoreas, the single ATA-100 drive that uses the I815E's ATA-100 interface, only achieved a 17K drive index, compared to the 20 - 21K offered by the Mirrored setup above. Moreover, the Mirrored setup should really be slower, as a result of incurred latency from dual "writes". Hence, this readily verifies the non-optimal implementation of ATA-100 via Intel's I815E controller. As a separate point, the FAT32 lags slightly behind a NTFS config, for a Mirrorer setup.
ATTO scores using NTFS drives (ATA-100 Mirrored)
ATTO scores using FAT32 drives (ATA-100 Mirrored)
Again, the mirrored setup exceeds performance offered by the stock Intel I815E ATA-100 interface, which only attains <30MB/s at its peak. Also, as the Sisoft Sandra benchmark exemplifies, the incremental prowess of NTFS over FAT32 in Win2K, is confirmed from its higher maximum threshold under ATTO.
From these startling results, a mirrored setup via the AMI chipset incurs little performance hit. Furthermore, it more efficiently implements the ATA-100 interface, even bettering a single ATA-100 drive using the I815E Storage Controller. This finding is definitely reassuring for potential RAID_1 users, who are concerned with sacrifices of speed for redundancy.