I recently configured a RAID 5 partition in Server 2008 with 4 RAID 5 disks. These disks are connected through a SATA expansion card that uses PCIe. This morning, I checked and they had finally finished synchronizing, and so I tried to do some speed tests.

Copying off the disks started pretty much fine - speeds began at > 125MB/s, then trailed down to about 70MB/s, which I found odd but not worrying. Writing TO the disks however is a completely different story. I attempted to copy some of my VM host ISOs onto the disks (~2-4 GB apiece) and this resulted in speeds of approximately 10MB/s. I tried copying both from a local disk (connected directly to the motherboard) and from another server ththe gigabit network and results were the same.

I checked the performance monitor while transferring the files and the only thing that stuck out was that my memory hard faults shot up to 6,000 per minute (spiking around 200/s) by explorer.exe. The system is running 2GB of DDR667 ECC RAM and a quad-core 2.3GHz opteron.

Is there anything I can do to fix this performance issue (buy more RAM? move the drives to a faster box?, etc) or am I just screwed so long as I stick to windows.