We do not measure performance on RAID volumes however; I can give you some troubleshooting steps you can perform to diagnose the issue.
- You can set both Hard Drives to non RAID in order to test them individually just to make sure both Hard Drives are OK. Since what you have is a RAID 1 volume the same information will remain intact in both Hard Drives, the information should not be deleted.
- You can update the BIOS of the motherboard, sometimes BIOS updates come with fixes for RAID issues.
I have latest BIOS and have removed disk from raid and all disks was OK. Then i have created RAID1 again, install clear Windows-7 x64 on it and after installation read velocity was excellent! After reboot, windows installs 113 updates and after it completes performance was again bad. May be somebody knows which one of 113 updates can be a reason?
Now i have some improvements. I have installed latest chipset drivers and Intel RST 11.6 software. My SATA disks is counted as SCSI and my RAID have Microsft Intel RAID 1 Volume SCSI Disk Device driver from Microsft ver 6.1.7600.16385. Now my read speed is near to 60MB/sec but write speed is 90MB/sec. I think that the problem is in the drivers. Because i have used WinPE disk with Paragon Hard Disk Manager to copy big file from RAID to standalone disk and read speed was 90 MB\sec. Please, give me some advice, how to solve this strange issue.