I'm to going to jinx myself now and tell you the settings I've used that MAY have fixed it. In NV control panel for the homeworldrm.exe I set the following: VR pre-rendered frames: 4, v-sync:on (off in game), triple buffering: on, threaded optimization: on, texture filtering: trilinear optimization: on, texture quality: high quality, negative LOD bias clamp, shader cache: off, anisotropic sample optimization: off, maximum pre-rendered frames:1, antialiasing gamma correction: off, antialiasing transparency 8x supersample, single display, optimal performance.
I've played through 3 missions and three hours so far with no return of this issue. I don't know what did it or if it worked permanently. I'll report back if I see anything different. It's a good game when it runs right.
oh also, I've been saving a lot also, maybe saving early and often helps. Also, also, I've not used Afterburner software, like I normally do.