SAS Disk Performance

[Mervin Cinq-Mars]

I am comparing 2 disks that I am considering for use in RAID 10 arrays for exchange 2007. Performance per spindle, not capacity is the priority. Both are DP SAS Hot Plug, 3.5" ENT series 15K
HP 450GB(454232-B21) and HP 300GB (416127-B21)

In the same series, higher capacity drives are often higher performing, but it appears to me that these 450 might be a newer better performing series as well.

has anyone benchmarked these, looking for max IOPS per spindle.

any experience is appreciated,