The chaps over at HardOCP take a further look at SSD RAID scaling under Windows 7 and what it all means to you. Here's a taster:

In our brief overview of RAID scaling under Windows 7 we showed you the limit that the popular ICH10R Southbridge places and yours PC's drive throughput. With SSDs continuing to drop in price the likelihood that people will string together four inexpensive, small drives in RAID-0 is increasing. It is important to know what limiting factors you may run into and to also help keep your expectations in check. Upgrading your PC's hard drive to a solid-state drive is possibly the single greatest upgrade you can perform right now to improve your experience, depending on what exactly you are doing with it of course.

Running more than one drive increases the time it takes to boot up into Windows 7. The increased overhead of RAID also makes it a slightly slower option when compared to a single drive in our case. Your mileage may vary depending on SSD used, motherboard used and which RAID card (if any) you use.