Need a reason to put a HD2900XT in a e-mail server?
But to get back onto the subject, Tarrari used RegEx Demonstration to compare a 2S Dual-Core Opteron with R600 powered boards and came up with interesting result

When running Kaspersky SafeStream, GPU powered search achieved 6.2 Gbps (775 MB/s) during scanning a hard drive array, quite close to maximum speed that RAID field could have provided, while DSDC Opteron processors were loaded between one and two percent. When Opteron was doing the same search, it was only 21x slower, at 295 Mbps, or 36 MB/s.