performance - Virtualizing a 32 bit guest on a 64 bit os

So I was wondering if anybody knew if there was any performance issues with virtualizing a 32 bit os, in my case 32 bit windows 7, on a 64 bit os, mac osX lion. I remember reading that running 32 bit processes in a 64 bit system can cause performance robbing situations with paging memory. Does this apply to virtualizing or am I misinformed?

I fully understand that the performance of the guest also depends on the amount or memory and cores you devote to your vm, but I was wondering more on the mechanics and the effects of mixing 32 bits with 64 bits.

Thanks everyone.

Answer

in theory it shouldnt be a problem. We could debate the semantics but If you are running any 32 bit programs on your 64 bit computer then you are running those programs in a virtual environment (which you likely are running 32 bit processes). But specifically speaking, when you are running windows on mac, your biggest problems are the challenges that your hypervisor will have in translating windows drivers to interact with the devices on your system. Usually this means the hypervisor works extra hard in keeping everything organized and translated appropriately. Bottom line, your biggest performance drop will have to do with how much power you pull from the processor constantly pegged out. If you are used to 6 hour mac battery life, say hello to 2hr battery life or less.