Limit guest to certain cores? Affinity mask

[scottgus1]

Here: viewtopic.php?f=1&t=54189 I learned that hyperthreading doesn't help and might hurt multiple guests running at the same time. I may have seen this (warning - anecdotal evidence ) when running two guests running the same program in each, where sometimes the programs are very responsive and sometimes one is sluggish while the other is smooth.

So has anyone used an affinity mask to control which core(s) the guest(s) run on? (Windows 7 64-bit host, XP 32-bit guests with 2 processors each, Core I7 cpu, hyperthreading on, Virtualbox v 3.2.12) Looking to force one guest to run on one host physical/virtual processor pair, the other on another pair.
I looked in the v3.2.12 help files, but "affinity" comes up "No Topics". Is there a setting to Vboxmanage-start a VM with an affinity mask?

[ChipMcK]

Google search affinity site:forums.virtualbox.org yields a large number of matches/hits

[scottgus1]

I google searched like you suggested, but I searched "affinity mask" and didn't get much. Thanks, I'll look around.

[Perryg]

Leave off the "mask"
https://www.google.com/search?client=ub ... 8&oe=utf-8

[scottgus1]

Gotcha. The right search words are the key!
Anyhoo, the search seems to say, setting affinity is a host-OS thing, not done in Virtualbox.
Thanks, all!