RAID 0 Performance with 2 drives, advice needed.

Need some advice from the pros and experienced users.

Have decided to try out RAID, got a pair of Seagate Barracudas 7200.11 320GB ( ST3320613AS, 7200RPM ).

Mobo is P5B Deluxe. Plugged em in, altered BIOS settings, CTRL+I after POST and created 2 disk arrays, one with 550GB (for games + downloads), other is 47GB (for OS). Then copied Intel Matrix Floppy Driver onto USB stick, inserted the DVD-ROM with OS (Windows 7 beta 7048) and started to install. Upon installation clicked "Advanced Install" and when the dialog for partition appeared, clicked "Drive Options (Advanced)" and proceeded to install the Intel driver from the USB flash drive. In a few minutes it was complete. I benchmarked with hdtune, hdtach and these are the results.

As you can see, the blue is the bigger 550GB, the red is 47GB. So here are a few questions.

Is it normal that the raid arrays size affects the read and burst performance of RAID, on 2 identical drives?
Since the 550GB array (can we call that partition?) has increased Random Access time, yet higher Average Read. Could you please explain please? Would 2 equal sized arrays have equal performance then? OR perhaps there was a mistake during installation, or Windows 7 is buggy, or some other factor.
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  1. The 'red' partition is a continuation of the 'blue' graph. Notice how the blue ends at about 130MB/s and the red starts at 130MB/s. Hard drives have higher speeds when reading from the outer layer of the hard drive platters. Think of a merry-go-round and how much faster you move when you are on the edge vs. near the middle at the same rotational speed.

    What has happened is you created the 550GB partition first which used up the outer (faster) part of the platters and then created the OS partition using the slower inner part of the platters.

    If you have the time, you might want to redo your installation, but make the OS partition first so it is made in the faster part of the hard drives.
  2. Ahhhh... interesting, thank you for such an educational reply! Will change the order. Do the speeds seem about correct for a RAID 0? Looking at the bench results on TomsH., they seem to have higher average reads, perhaps they used one raid array partition using the whole platter, and on that basis the average was higher.
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