As others have said, the CPU seldom is the bottleneck in a database server. The only interesting thing to me about newwer processors is the tendancy toward more efficiency. Performance per Watt will determine long term costs. The number of cores and gigahertz just aren't a determining factor for a database server unless it's on a shared machine that is also doing other processing.

I/O and disk configuration are the real problems. I can't tell you how many times I've seen other people setup database servers with just a single RAID 5 array and say "now all reads and writes will be load balanced across all the disks!" and I just smack my forehead. The disk heads will be jumping back and forth constantly between TempDB, transaction log, data pages, index pages, etc, and will bog down disk I/O and thus your database. If your disk setup is bad, or network setup is bad, all those CPU cores will be twiddling their thumbs waiting for something to do.