Found a HP Support site that has AMD RAID Drivers to download for WIndows Server 2008 R2. Don't know if you tried this link before or not: Drivers & Software - HPE Support Center. (Copied website from link):
Drivers & software
SGI product documentation and software downloads are currently being migrated, please visit the SGI portal for your SGI documentation and software needs during this migration period.
AMD SB7xx/SB8xx Chipset Windows Server 2008 and Windows Server 2008 R2 64-bit SATA RAID Driver
By downloading, you agree to the terms and conditions of the Hewlett Packard Enterprise Software License Agreement.
Note: Some software requires a valid warranty, current Hewlett Packard Enterprise support contract, or a license fee.
Okay, when you click on the AMD Link - JIVE prevents you from accessing that site.
Best thing to do is open a EMAIL SUPPORT TICKET with AMD Support so that they can give access to that site or give a link to be able to download the latest RAID Drivers from AMD. Here is the link for the Email support (they will assign someone to help you with this problems, Hopefully): Email Form .
Yes, that's the roadblock I ran into when trying to follow the link from HPE's site. Thanks for your suggestion of using the support request from, I have followed up on that and will update back here on progress / results as and when...
Just to update as promised: the support request paid off and the team were able to supply me a link to download the correct drivers. The link was a temporary FTP one so there's no point in my posting it, so I suggest anyone else looking for the drivers makes the same request in the support form. If all else fails PM me and I'll happily put them up on my FTP server and provide a login to download them.