The two most notable features of Apple's latest MacBook Air refresh are power-efficient Haswell processors and fast PCI-Express-based storage drives. Those laptops are on sale now. On the PC side, we can expect Ultrabooks with Haswell to begin rolling out in the next few months, definitely in time for back-to-school shopping season. And some of those new ultrabooks will get PCIe storage, courtesy of Samsung's newly announced XP941 series of SSDs. Samsung, who also makes the flash storage for Macbooks, is now mass producing these fast drives, which come in the 80mm x 20mm M.2. form factor. Drives will be reach a capacity of 521GB, and Samsung claims sequential read speeds of up to 1,400MB/s. Real-world performance will likely be in the 800MB/s range, according to early benchmarks of PCIe SSDs.