So, I've been running a 600GB raid0 array for a while now... 2x 320GB Seagate SATAII drives, connected to my C2D 2.33GHz MBP via an Expresscard SATA controller (Sil 3132). That setup gave me very good performance; consistently above 140MB/s read and write. Today I got in a 5 bay port multiplying SATA case, along with 4 new seagate 320GB drives... so now I have 6 drives total. Doing a raid0 stripe across all 6 drives gives me around 112MB/s, though sometimes even slower... Adding drives to a Raid0 should speed it up, not slow it down! A raid 10 (stripe and mirror, 3 drives in each striped set mirrored), gave a dismal ~55MB/s. ...Single bare drive performance is just over 79MB/s read and write. I'm in the process of building a raid 5 (using Silicon Image's SATA RAID 5 Manager) to test its performance, but I'm not too hopeful... The theoretical maximum for this setup is ~320MB/s, which I really shouldn't have any trouble hitting with 6 drives raid0'd. (This is the 2.5Gb/s limit of the express card slot... the SATA II limit for all hardware involved is 3Gb/s).... Even if for some strange reason the setup was defaulting to SATAI (and it shouldn't be... all hardware is SATAII compliant and all drives are jumpered to SATAII), I still should be getting 1.5Gb/s, or ~192MB/s. Any ideas as to why I'm getting such crappy performance?