VMware Fusion vs Parallels Revisited

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I recently made an entry about trying out Parallels Desktop for the Mac. My two-week trial key still has a few days left on it, but I made up my mind days ago.

For what I do (Windows and Linux software development and a few Windows games), Parallels simply offers much better performance. Much better — it’s at least twice as fast as VMware Fusion on memory-intensive programs like games and compilers, and sometimes up to four times as fast. (Anything that isn’t memory-intensive they run at pretty much the same speed.)

I wasn’t able to find a single program that I use that it couldn’t run. The games I’ve tried (Age of Empires II and III so far) are very playable, far more so than under VMware. Claws Mail and GCC under Linux both still spend some time in the “IOwait” state on occasion, but far, far less than they did under VMware.

Visual Studio 10 on Windows is still a little slow, again due to disk accesses, but also again it’s two to four times faster than under VMware. I don’t have a Boot Camp version of Windows installed on this machine, so I’m not sure how it compares with running Windows as the primary OS, it might well be near-identical. Bumping up the memory on the Windows development VM would probably help, but I have two other VMs that I run regularly and I’m pushing the limits of this machine’s 8GB already, so I haven’t tried it yet.

I think I’ve figured out why VMware is so much slower. From various discussions in the VMware forums, it looks like it uses some kind of disk-storage of memory, probably a mapped file. I’m sure that greatly simplifies memory management, and probably lets you run more VMs than you’ve got the memory for (which I’m not sure Parallels can do), but it also causes the speed problems when large chunks of memory change quickly, as with compiling. That would explain why there’s much less of a speed hit if you run less memory-intensive programs, though of course that doesn’t do me much good.

Other than one minor bug, I’ve only seen one problem with Parallels. I had just suspended a large VM, and the system hadn’t finished writing it yet, when I tried to switch to another VM. The program immediately stopped responding to input of any sort, in VMs or in its menus; all it would give me is the “beach ball” cursor that says it’s too busy to respond. After a bit the system finished writing, but the beach ball remained and it continued to ignore input, though programs were still visibly operating in the remaining VM. The system claimed Parallels wasn’t responding, so I finally instructed it force-quit Parallels.

I expected to have lost what I was doing in the remaining virtual machine, but to my shock and amazement, when I restarted Parallels after a few seconds, the VM popped up immediately, still running! I suspect that the user interface code was running in a separate process than the VMs, and what I killed was only that; restarting it immediately reconnected to the still-existing VM.

All in all, I’ve been very impressed with Parallels. I took the plunge a couple days ago, buying a copy using the $30 “competitive cross-grade” from VMware Fusion. The odds are that I’ll be persuaded (or coerced) to switch back to VMware at some point, but for the foreseeable future, Parallels has my business.

EDIT, 2011-10-01: I’ve finally found a game that Parallels won’t run. Master of Orion II, the Windows version (as opposed to the DOS version, which I haven’t tried yet, but I expect would work). VMware Fusion wouldn’t run it either, locking up at about the same place, and the bit that it would run ran at about the same speed as molasses in February. Not really a problem, I can always run the DOS version in DOSbox under Linux.

10 Comments

  1. It also sounds like a lot of the problems that made Parallels have a reputation for being (only) somewhat faster than VMWare but flaky are gone too. Looks like when I’m in the market for a VM software update, which I may be once I’m running Lion, I’ll look at Parallels.

    • I’m sure it is only somewhat faster, for most programs. Unfortunately the programs I use most utilize a lot of memory.

      If you want that $30 competitive cross-grade price, keep in mind that it’s only available for a limited time. Their website doesn’t say, but this page claims that it’s only good until September 30th — two days from now.

      • Oh great, now you tell me. I had Rosh Hashanna and Shabbos before I read that, so now maybe its too late…. (Checks page… No, it isn’t! 🙂 )

        • Sorry, I tried to let you know as soon as I could. I’m glad to hear that it’s still on, though I’d expect it to vanish any day now.

  2. Pingback: VMware Fusion vs Parallels Revisited « Geek Drivel | Linux Affinity

  3. I currently have a license for VMWare Workstation 6 and am currently trying v8 prior to upgrading. So far I’ve noticed lagginess in the host network regardless of whether Workstation is running or not and when it is running my system periodically freezes for a minute or so, then continues like nothing happened.

    At this point I’m considering giving Parallels for Windows a try before commiting any more money into VMWare by upgrading WorkStation.

    My one thought though is that while Fusion may have been the “Red-headed step-child” of VMWare, the Windows version looks like it may be Parallels “Red-headed step-child”.

  4. I don’t think I’d ever heard of Parallels until I started using a Mac. I don’t know whether that’s because their PC version isn’t up to the level of the big-name offerings, or because the big-name offerings on Windows systems are so good that no one looks at the alternatives. I know I never had enough of a problem with VMware (under Windows or Linux) to look at anything else.

      • Apparently it does, though by the version number discrepancy, I’d say it’s a more-recent addition. It makes sense, once you’ve got the technology to make such a product, porting it to different OSes on the same architecture should be a snap.

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