CPU usage: is this necessary?

[Carlo]

So:

I run a machine with a quad core CPU, and after overplaying games like Crysis and Mass Effect, I want to get a little retro.

So, I pull out Gens and Snes9x, load some games, and have a good time. The thing is, I'm really irritated by the fact that a program emulating 32-bit games is throttling one of my 2.4GHz cores to full usage.

Does it strain my CPU? No. Overheat it? No. Does it seem a little uncalled for? Yes.

And the crazy thing is, years ago, I used these emulators on a 850MHz P3 and it pushed that thing to 100% usage, so naturally, I figured a single 2.4GHz core could keep it tame. Guess not.

Is there a way to change the settings in these emulators (or any emulators) to keep the CPU usage lower? Like, stable, NECESSARY low?

[Jale]

The emulator was designed to use one core, so it may be using 25% of it. Is it normal? Yes, it is. About the full usage of the CPU it depends on the features of this emulator. Remember that emulators are CPU intensive applications.

[FatTrucker]

Does the percentage not refer to the amount of the core dedicated to running processes?. What I mean is that by reporting 100% doesn't necessarily mean that core is maxed out and running full whack, just that 100% of its resources are available to the emulator if that's the only program currently running and asking for processor time. If you run something else using the same core at the same time you'll probably see the percentage change with no performance hit as the processor allocates some processing time to the other app as well.

[Carlo]

Exactly.

What I'm saying, it absolutely doesn't need 2.4GHz to run - but it hogs up that core, anyway.

[FatTrucker]

It shouldn't hog it, only if nothing else is running on it. If something else requires that resource then the processor will allocate some load towards it otherwise it can dedicate itself to mame.
I thought the whole benefit of multi-cored processors was so you could dedicate different cores to different programs rather than having to split its time between them as a single core does. So surely its doing exactly what a multi-core processor is meant to do?.