I used to have two 80 GB hard drives running IDE RAID 0 (striping) on Windows 2000 with no problems. Then I added two additional 80 GB drives making a total of 4 drives, changed to RAID 0+1 (striping and mirroring), and switched to Windows 2000 Advanced Server. The problem is that when I move the mouse, it hangs for about half a second. Seems like the whole system is slower. Is this because of the mirroring? I have no idea whats wrong. Thanks.