I don't quite understand the significance of differences between the various Dell RAID controllers for my scenario, it would be great if you guys could help me choosing the right one. I don't want to burn money by buying something for no reason, but at the same time ensure that I'm getting what I need.

For my Dell R710 2U server with **6x** 146 GB 15K RPM drives, I have the choice between the following controllers:

* SAS 6/iR Integrated, x6 Chassis [automatically included]
* PERC H200 Integrated RAID Controller [adds **$199**]
* PERC 6/i SAS RAID Controller, 2x4 Connectors, Internal, PCIe, 256MB Cache [adds **$299**]
* PERC H700 Integrated RAID Controller, 512 MB Cache [adds **$499**]
* PERC H700 Integrated RAID Controller, 512 MB NV Cache [adds **$699**]
* PERC H700 Integrated RAID Controller, 1 GB NV Cache [adds **$799**]

In case it matters, the server is going to run Windows Server 2008 R2, SQL Server 2008 R2, and IIS, and basically host various websites with varying degrees of complexity and SQL activity.

I want to run 3 RAID-1 arrays (2 discs each), with the OS/TempDB etc. on the first array, SQL data on the second array, and SQL log on the third array.

Really appreciate your help. Thanks!