HP puts a low-power laptop on the desktop and charges a premiumMost all-in-one PCs make extensive use of notebook technologies: The processors are low voltage, the GPUs are mobile designs, and the optical drives are low profile. This tends to endow all-in-ones with a natural price premium, because compact, lower-power components add cost. Be that as it may, the $700 HP Pro All-in-One seems a tad overpriced—particularly when you consider that the nearly identical home version, the Pavilion MS200, costs $100 less.We don’t think this boost is entirely an attempt to gouge corporate buyers, though. For one thing, the Pro All-in-One ships with the 64-bit version of Windows 7 Professional, which adds domain networking, Windows XP mode—a virtualized PC running Windows XP—and network-backup capability.The MS218 consists of a monitor (with all the workings of a PC built into the same enclosure), a keyboard, a mouse, and a 120-watt external power brick. Although efficient (the entire PC draws just 36 watts at idle), the brick seems to be overkill. Even when running system-intensive tasks, we never saw power consumption rise above 66 watts.