SCSI vs SATA

We need to upgrade a postgres server. I'm not tied to these specific
alternatives, but I'm curious to get feedback on their general
qualities.

SCSI
   dual xeon 5120, 8GB ECC
   8*73GB SCSI 15k drives (PERC 5/i)
   (dell poweredge 2900)

SATA
   dual opteron 275, 8GB ECC
   24*320GB SATA II 7.2k drives (2*12way 3ware cards)
   (generic vendor)

Both boxes are about $8k running ubuntu. We're planning to setup with
raid10. Our main requirement is highest TPS (focused on a lot of
INSERTS).

Question: will 8*15k SCSI drives outperform 24*7K SATA II drives?

-jay