For SQL Server usage, modern Intel processors perform much better than modern AMD processors. You would want to be looking at something like an HP DL380p Gen 8, with Xeon...

Jonathan and Gail are correct here. Prior to SQL Server 2012, the Max Server Memory instance level setting only controls how much memory can be used by the Buffer Pool....

It seems like you are getting regular CPU spikes to 100% every night at about midnight. Is that when your full backups occur? Are you using 3rd party backup...

The main interesting thing I saw is that you are on Build 2714, which is fairly old (SP1 CU2). I would want to get SP2 CU2, Build 4272 installed....

You can only use database mirroring to upgrade from SQL 2008 to SQL 2008 R2. It lets you mirror from the old version to the new version, and then failover...