Summary I have replaced two Seagate PATA 160 drives with new WD 2TB Green drives on my server and am seeing really poor performance writing to the array. Configuration The hardware consists of an ASrock 939NF6G with the nForce 430 providing 4 SATA-2 ports with RAID support. There is 2GB of DDR-333 over 4 sticks and the processor is an Athlon 64 3500 (1mb cache) - Cool 'n Quiet is enabled. The O/S is Windows 2003 Server 32bit. Of the two PATA drives, the newest (a 7th Gen) 160gb drive replaces an old WD 36gb Raptor as the Boot drive. I configured the array with a 64k block size and think I formatted it with NTFS and a 4096 bytes allocation size. The drives are the new EARS drives with 4k sectors. Problem in detail I have tried writing a batch of, approximately, 4gb ISO files across both WIFI/G at around 100mb/s or 1000T wired Ethernet from my Windows 7 Media Center. Windows told me the files were being written at around 5mb per second! I then thought I'd try writing the same files to the Seagate boot drive and it wrote the same files at around 60mb per second.... there is something very wrong here! I would expect the new drives to be MUCH faster than they are - at least equal to an old 7th gen Seagate! I appreciate the a Mirror RAID array slows down writes since each byte is written to two drives at the same time but not this much slower - what have I done wrong? Also I appreciate that the NVRaid is operates at CPU/Driver level but whilst the CPU is not the most powerful, the machine is still idle when the files are being written... cpu usage barely peeks over 5% and the clock speed stays pegged at 1ghz due to cool 'n quiet/power now - is this the cause? Is it the RAID block size or the allocation size? I'm sure the allocation size is appropriate for the new drives since the sector size matches the O/S allocation size. Maybe it's the drivers? For the server O/S I had to use the XP drivers which are the Nvidia 1107 all-in-one driver set from the ASRock web site. Any ideas?