1 or 2 cores for the guest OS?

[Synthetic_Mind]

Ok I have Mac Book Pro with a 2.5 GHz Intel Core 2 Duo, 4 GB 667 MHz DDR2 and Mac OS X Snow Leopard 10.6.4.

I have Virtual Box 3.2.8 r64453 and installed Windows XP 32 with SP3 with latests updates and VBox additions as my guest os.

My question is a simple one and even stupid but I want to know anyway.

VBox give you the option to use 1 or 2 cores (or more but my CPU won't be able to handle them) while running the guest OS. I want to know what would be a better option. To run one core or to run 2?

I've read that you should leave at least one free core when running multiple guest OSes but I'm not sure if this also applies if you are running only one guest OS with a CPU with only 2 cores.

What would give me a better performance specially when running WInXP 32?

Right now I'm running WinXP 32 with 2 cores and they show up perfectly fine under the task manager.

Thank you in advance for your wisdom.

[Sasquatch]

As long as you don't notice any slow down, and you install Windows with more than one core from the start, things shouldn't matter all that much. But keep in mind that once the VM uses both cores completely, the Host can and probably will respond slowly. If you keep one core free, the Host will not slow down when the Guest goes nuts, so to speak.

[Synthetic_Mind]

Thank you brother.

That explains why I sometimes get serious host slowdown while running the guest OS.

I'm gonna use one core and see how it goes.

[Sasquatch]

It's best to reinstall the Guest OS after you switch cores, as the proper kernel will then be installed for it and it runs better than when you would change the kernel after you installed it.