You don't list your operating system if its XP try the suggestion below:
Actually thats about where its supposed to be. If you are expecting your transfer rates to double when you use a striped volume it doesn't. I mistakenly thought the same thing. Although your benchmark IS close to double mine. (when I did a benchmark with my raptor pg.11)Other than getting a controller card you can improve performance by enabling cache writing and enabling the advanced performance feature on the RAID set-up.
To do this go into right click the "my computer icon" choose manage. Click on device manager then click on the plus sign next to disc drives on the right. You will see your RAID set-up. Right click that and choose properties. click on the policies tab. Check the box "enable cache writing on this disc"
and also check "enable advanced performance"
Make sure you read the notes under these settings unless you have a UPS (battery back-up) you risk data corruption or loss.
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