SINS is pretty much a single-core game. An additional core will only be used to pre-cache textures, after that everything runs on a single core.

I would say one should have at least 2GB of RAM (which you have) for SINS

I doubt setting core-affinity for SINS would be of much help. Late-game SINS is simply put "a beast" so no shock there about bringing things to a crawl.

A 256MB video card may be having trouble with some of the better/larger textures in-game so yes you could try turning all graphics options from "highest" to "high", disabling "bloom" and lowering the AA (anti-aliasing).

Are these "more than 5 players" people in MP or AI in SP? If it's MP then you known since SINS is P2P that the slowest pc in the bunch will limit the rest of the players so it may not be your pc causing the slowdown. If however it's SP then the problem with the AI calculations, in which case...try setting "fleet size" to small and playing with less AI.

One thing I've also been doing for years with great success.....is to make sure my pagefile is always set to at least 2.5 X the amount of installed RAM.

thanks,

the Monk