Velociraptors raid 0

It's a hair lower than mine, but in the right neighborhood to be sure. As for the burst rate, you can improve performance by downloading the Intel Matrix Storage Console and enabling the write back cache on your RAID volume.

Like he said enable write back cache.

Enable the write back cache. It won't change anything on the drives, you won't have to reinstall or anything, and it should slightly boost performance (and massively boost the burst rates)

True. By default in windows though, some level of write caching is enabled on the OS disk, so it shouldn't hugely increase the risk. I've never had any trouble. (You probably want to disable all write caching when experimenting with new overclock settings though)

NTFS is pretty robust, but even though write caching can be done for data it does use a specific order of write-through operations when updating critical file system structures. The problem with write caching is that the I/O subsystem could physically write the data in a different order, and if a failure occurs in the middle then it could cause problems.

It's pretty unlikely, but just like in overclocking there's often a tradeoff between performance and reliability. IMHO it makes sense to understand the ramifications of the decisions you're making.

The ridiculous burst rate is because you have the write back cache enabled. My pair benches as follows:

Min: 160MB/s
Max: 270MB/s
Avg: 215MB/s
Access time: 7.3ms
Burst rate: 2813.7 MB/s (also known as 2.748 GB/s)
CPU usage: negligible

My burst rate is higher because the intel controller is using system RAM for bursts, rather than anything on the hard drives themselves (since 2.75GB/s is quite a bit faster than you could physically deliver over a pair of 3Gb/s SATA ports). My RAM is 1600 7-8-7-22 compared to your 1458 8-8-8-22, hence the higher burst rates. If write back cache were disabled, it would only be a burst rate from the drives themselves, which is why the OP has vastly lower scores (in fact, the highest burst rate possible on a pair of SATA 3Gb/s drives with no external caching is 600MB/s if they completely saturate both channels of the controller).