Boot Camp vs VMware Fusion 5

It's completely the same, and here's why.

In Boot Camp, Windows is installed in a second volume of your hard drive. If you get malware and it tries to copy to another volume, it won't be able to do that, because Windows can't write in the OS X volume, so you are safe. Also, OS X isn't affected by Windows viruses. In a virtual machine, the Windows hard drive is a file stored in Documents folder that acts as a virtual hard drive, but Windows can't copy to the OS X partition even if you install the drivers that VMware Fusion provides.

Apart from that, as you want to run Windows XP, you won't get a big difference if you run it in Boot Camp, so you may want to use it in a virtual machine

To add to what Mende1 stated, the main advantage to running a virtual machine over bootcamp is that you don't have to reboot the mac to switch back and forth. If you have sufficient ram and processor speed, the VM would be more accessible. It depends on the resources of the system.

HTH

If you want to run windows xp there is only one option. That is to run it in a virtual machine because you can't install xp in boot camp anymore. Appl has limited boot camp to using windows 7 or 8.

As to the virtual machine software program you use you should try oracle virtualbox. It is free and works very well.

Since you are so concerned, rightly so, about viruses it is a wonder that you want to run XP rather than a more secure Windows 7 or Windows 8. XP is getting very old and security on XP is not nearly as good as on the newer OSs.

Virtualization is safer than Boot Camp in the sense that you can take snapshots (not Time Machine snapshots) of the virtual machine and restore them easily if something goes wrong. Clearing a malware infection from a Boot Camp volume wouldn't be as easy.

Windows XP is an operating system that requires less hardware than a newer version. That's the reason why I told you that performance will be similar if you run it in a virtual machine or through Boot Camp, thing that wouldn't happen if you do it with Windows 7, a more recent operating system that will run better through Boot Camp because it uses newer hardware and knows how to use it fully to get the best performance

I disagree slightly with the post above. No matter what operating system you run, Win XP, 7, 8 or a version of Linux, it will always run better installed directly on the systems hardware than it will in a virtual machine.

Now if you run xp in a vm and 7 directly on the hardware I think 7 would run better overall as it has direct access to all the physical hardware in the system. Any os running in a virtual machine uses virtual hardware, software that mimics hardware, and only has limited interaction with the physical hardware.

If that is the only program you are going to use in windows it is a waste of hard drive space to install win 7 in a boot camp partition. Do some checking on the programs forums, if there are any, or a Google search for running that program in a virtual machine. It may run just as well in a vm.

Yes I am. Whenever you partition your drive you set aside a certain amount of space that may or may not be used by the os and programs you install and you always need more space then the os and programs use so the os runs properly, approximately 10% (at least) more than is really needed. With a virtual machine you create a virtual drive of say 100GBs, remember it is a virtual drive. What is physically used on your physical hard rive is only what the os and programs take up. But to the os running in the virtual machine the drive looks like that 100GBs of space you allocated in the virtual drive. The only bad part about that is once the virtual drive grows, from installing program or copying files to the virtual machine virtual drive, it can never shrink back down. So if you installed 5 programs that take up 25GBs of space and then removed, uninstalled, 3 of them that frees up 15GBs of space the virtual disk size on your physical drive would still use that extra 25Gbs of space. With some vm programs there is a feature to compact the virtual disk, VMware Fusion includes that feature, but it will never recover all of that 15GBs of physical disk space you used installing those programs.

All in all virtual machines are very hard drive space efficient. That is if you don't willy nilly install and uninstall program.

The smallest size I've managed to whittle an XP VM on Fusion is 6GB. But that's a barebones setup, no apps or anything.

Also worth noting that a VM runs as an idealized PC. Fusion makes the guest OS think it is running on a very specific set of components, with no direct access to the real hardware. Fine and dandy for most uses, but some finicky or heavily DRM'd programs may refuse to run. Games that don't fall mostly in the finicky category.

Lastly, VM is not equal to bare metal, performance-wise. Very I/O or graphics-intensive programs may underperform in a VM environment to cause an unsatisfactory user experience. Games are prone to fail like this.

Edit: Fusion has an option to shrink a Windows VM once you've emptied out the cruft, to return to its original size, yes.