I'm looking at the screenshot, and do not understand. Where is that "poor storage performance"? All I see are results typical for given configuration: traditional HD, with slow interface. BTW, where did you measure it? I mean, where on the drive? Traditional drives do not have constant i/o speed, but rather constant bit-density. So on the outer track you get higher i/o (because higher number of sectors per cylinder) than on the inner track. This ratio might be 2:1, or even more...
You want higher read speed? That's simple: add more drives to raid0-stripe, switch from sata/3Gbps to 6Gbps (or sas), or switch to SSD.
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If you found my answer useful please do *not* mark it as "correct" or "helpful". It is hard to pretend being noob with all those points! 😉