If you're not up to speed on your storage form factors, here's the quick and dirty rundown. Most desktop setups come with 3.5-inch drive bays, traditional notebooks typically ship with one or two 2.5-inch drive bays, and devices like ultra-thins, netbooks, some nettops, and tablet PCs usually employ 1.8-inch bays.
Now that you've graduated Storage 101, let's move on to solid state drives (SSDs), and specifically, a pair of new models from OCZ. Put more accurately, the memory maker took two existing SSD families -- the Vertex 2 and Onyx -- and put them under a shrinking ray, much like the one used in the movie "Honey, I Shrunk the Kids," only far less powerful. The result is OCZ was able to deliver 1.8-inch versions of each drive without sacrificing any performance in the process.
"Solid State Drives provide numerous benefits to mobile users including improved performance and reliability as well as lower power consumption versus traditional hard drives," said Alex Mei, CMO of the OCZ Technology Group. "We are now introducing two new drives that are designed to cater to the entire range of mobile applications including the Vertex2 1.8-inch which delivers the same performance as our popular 2.5-inch version in a smaller form factor for customers looking to achieve maximum performance on the go, and the new Onyx 1.8-inch which is designed for consumers looking for a quality SSD that is aggressively priced and is ideal for netbooks."
In other words, these are the exact same drives, only smaller, so you can expect the same 285MBs read (Vertex 2) and 275MB/s write (Vertex 2) speeds.