mdraid0 performance

I'm wondering why i get such low numbers from my mdraid0 RAID setup. I've setup 2 mdraid0 of 2x SSD partitions and both perform like a single SSD when it comes to IOPS, but better with seq. read. Here are some numbers: First RAID0 of 2x Intel S3700 400GB, using only 100GiB partitions for...