I can't offer much advice, but slaves should be frame capped at 15-20 FPS. There's no need for them to run higher than that. Even 10FPS is good enough in many cases.

To set the max foreground FPS, where # is the FPS limit you want

/console maxfps #

To set the max background FPS, which is the non-active window

/console maxbkfps #

Second, you can always test for yourself by getting a few trial accounts.

I'll leave the hardware stuff to people who know what they're talking about.