It's hard to imagine what more a Windows-on-Mac virtualization application might do given the software's undeniable maturity. And the new Parallels Desktop 7 shows just how hard that question is to answer. If Mac-on-Mac virtualization — the big new capability in Desktop 7 — is the most important next step, then Parallels should have taken a little more time to make it easier, especially for developers and IT users.
Windows 7 users might see a speed boost. Although Parallels Desktop 7 promises to run graphics 45 percent faster than Version 6, I saw a mere 8 percent improvement in 2D rendering, based on the PassMark benchmarks. I did get a 44 percent boost for 3D graphics, so gamers and simulators should see a notable improvement. But note that Parallels Desktop does not support DirectX 10, so some video-oriented games and applications won't run.
Overall, PassMark showed Windows 7 running 9 percent faster in Parallels 7 versus Parallels 6. That's not bad, but keep in mind such synthetic benchmarks tend to overstate what you'd get in real-world performance. For most users, I don't think it justifies an upgrade.
Parallels 7 vs. Parallels 6
Parallels Desktop 7's other enhancements include support for Mac OS X Lion's full-screen mode and Mission Control interface, support for the AES-NI encryption standard for Windows VMs, and easier sharing of printers and the Mac's built-in camera. Version 6 can run on Lion as well, but it does not support Lion's new gestures or Mission Control.
The $20 Parallels iOS app from the Apple App Store lets you access both Mac OS X and Windows VMs, as well as the underlying Mac OS X, from an iPad or iPhone. The previous Parallels app for iOS did that just for Windows VMs. Of course, virtual desktop clients for running Mac OS X on iOS are easy to find, and there are good free ones, so the main value of Parallels' enhanced iOS app is the unified virtual desktop. Plus, the iOS app works with both Parallels Desktop 6 and 7, so you don't need an upgrade to Parallels Desktop 7 to take advantage of it.
These Parallels Desktop 7 enhancements are welcome, but I'm not sure they're worth the cost of a $50 upgrade ($80 for the full version) to most users — especially just nine months after Desktop 6 was released. What might entice you to upgrade to Version 7 is Parallels Desktop's new ability to create Mac OS X Lion VMs, with which you can run virtual Mac instances on your Mac, such as for beta testing or configuration testing.
Previous editions of Parallels let you set up Mac OS X Server VMs, but not VMs of the desktop OS. Apple removed its restriction against desktop OS VMs in Lion (you're permitted to run two Lion VMs on your Mac), and Parallels quickly enabled that capability in Desktop 7. (Note: You still can't create VMs of previous Mac OS X desktop versions, as Apple hasn't changed the licensing terms for Snow Leopard or earlier versions to allow it.)
Virtualizing Mac OS X Lion
Unfortunately, Parallels Desktop 7 gives you only one easy way to install Mac OS X Lion on a VM, but it's painful: You download the 4GB installer file from the Mac App Store, which means waiting for one or more hours.
The way Parallels handles Mac OS X installation via the Mac App Store means you can create only clean installs of Lion; there's no simple way to transfer an existing Lion environment to the VM as there is for Windows VMs.
If you're a savvy Mac user, you can get past these issues. For example, you can use the Windows DVD install option to select a Mac OS X installation image from your startup disk or from a USB-connected storage device. But you can't use the Install Mac OS X Lion file that you downloaded from the Mac App Store. Instead, you have to open that application package(Control-click or right-click the Install Mac OS X Lion.app file and choose Show Package Contents), then search for and copy out the InstallESD.dmg file containing the disk image. The installer file is deleted by default once you install Mac OS X Lion, but there are ways to prevent that, as well as to access the hidden copy on your Mac. Apple also has a tool that lets you create your own installer image on a disk or thumb drive. Wherever the installer resides, the trick is you have to install its internal .dmg file, not the .app package file containing it.
When you install Mac OS X Lion in the VM, you can use the option to copy an existing Mac OS X Lion environment from a Time Machine backup, or you can use the Migration Assistant utility to transfer another environment's settings and apps to the VM. But you can see such external environments only if they are on USB-connected storage devices and you've told Parallels to assign that USB device to the Mac VM, which you do via its Devices menu's USB submenu. (Note that the name of the USB drive will not likely match the name of the disk partitions on that drive.)
Sadly, Parallels does not see storage devices connected by the speedier FireWire technology or by the even faster Thunderbolt technology — the kinds of technologies that Web and application developers would want to use when running Mac OS X from the external disks from which they'd likely be migrating Mac OS X environments. Most such drives — but not all — have USB ports, so you can connect them via USB for the VM setup and then use FireWire or Thunderbolt from that point on. Just note that non-USB drives will be visible within the VM only as folders, so any apps that need to see them as drives, such as Disk Utility or Time Machine, will not be able to connect to them.
Finally, I could not install a beta version of Mac OS X Lion, which I've been using to test iCloud as a registered Mac developer, over a VM installation of OS X Lion; the boot screen hangs up. The developers at Parallels said they hadn't tested the installation of beta Mac OS X versions in a VM, but were surprised I was having trouble. This may reflect a bug in Parallels Desktop or an issue with this particular version of the beta Mac OS X installer. I'll update this review if we're able to resolve the issue.
These installation limitations mean that Parallels Desktop 7 is not nearly as flexible as what Mac OS X lets you do so easily with physical disks. After all, portable hard drives are cheap — and quite flexible to use for having multiple Mac OS X instances.
The shortcomings suggest that Parallels Desktop's installation method for Mac OS X VMs was rushed to get a product out the door quickly after Lion's release — after talking to the developers at Parallels, it's clear they
