When solid state drives finally made it to the consumer market roughly 5 years ago no one could deny that they offered superior data transfer speeds compared to regular mechanical drives without at the same time producing noise and heat. However no one also could deny that such solutions had but two large drawbacks and that were their prices (for most people) and limited storage space. So the solution was quite simple for some and so back then Seagate immediately started working on a hybrid drive by marrying a standard 2.5" mechanical drive with a rather large storage capacity and a rather small 2.5" SSD. The idea was to use the HDD section to store everything you threw at the drive and the SSD section to cache the things you used mostly on your daily activities and thus provide you with increased speeds. The result was the Momentus (and later on the updated Momentus XT) hybrid drive which actually did quite well in the end and did produce better results than regular mechanical drives. Other manufacturers also decided to marry a regular HDD with an SSD but they followed a whole different path and so some did so with dual 2.5" internal enclosures (for example RAIDON), others by introducing cache SSDs and Hybrid PCIex models (OCZ) and a few by following the old RAID 0 solution which basically divides all your data evenly on two or more disks for increased performance. RaidSonic just recently jumped on that last wagon with their ICY BOX IB-RD2121StS 2x2.5" to 3.5" HDD/SSD RAID Converter and naturally we just had to check it out.