Parallels or VirtualBox to run Clampfit on a MacBook Pro running Yosemite 10.10.3? I'm completely new to Macs and always used PCs so far.

Said so, I'll try to be as much specific as I can.

I just bought a MacBook Pro running Yosemite 10.10.3 and am considering installing Parallels or VirtualBox (or?) to run Clampfit (a Windows-only compatible analysis software) on my Mac.
My Windows OS of choice would be XP or Windows 7 (unless otherwise suggested here).

My question is:
which between Parallels and VirtualBox would be affecting the least the performance of my machine?

Please note:


most likely I would not need to run softwares requiring large amounts of memory together with Clampfit
I already have Parallels


Thank you very much for your help.

Massi
I suppose the VMWare is also an option.

However, as you know with Parallels, you can restrict the resources that are available to Window, such as the number of CPUs available between Mac and Win, the memory, and the video card memory.

Whereas a typical configuration might be to share these resources equally between Mac and Win, in your case it makes sense to reduce the resources for Win (and consequently for Clampfit), and you can fine-tune this to your liking.

I'm not certain about how much you can limit the amount of hard drive space available for Windows. I always went with the suggested 64 GB, and I don't recall if you could reduce this.