virtualbox.org

Dear

I would like to define a limit of the CPU use for each Virtual Machine

Like :

For specific VM use max 800Mhz processor

Is it possible to do that ??

No, not possible. You can only provide how many CPUs the Guest sees and thus can use. Of course you can give it more CPUs than you have but that's not advised.

do you know if it planned in next releases ?

I'm not a dev, and there isn't a public roadmap either, so sorry, I don't.