Gentlemen,
The dependence upon multiple cores/threads to compensate for lower core speed is a very complex matter; more so than in most games like FSX.
QuestViewer, which is the graphics engine and also the controlling program for the game, uses only one core. It calls many external routines to accomplish tasks. In some cases, these routines can run on other cores. The net effective gain in processor speed is hard to predict, and can vary from build to build.
Another thing to be considered is: While turbo boost can, when running on a single core, effectively over-clock that core to sometimes double its speed, that capability is often disabled in the bios by the manufacturer to avoid a lot of support calls.
Results in running SSE vary considerably among users with nearly identical systems. Good performance on the demo is encouraging because it is essentially the full game, but with a limited number of ships and missions.
Performance in FSX or other games is not a very reliable indication because SSE differs from them in the very heavy burden on the CPU before the next frame can be rendered. This means that CPU speed is the dominant factor in determining frame rate, rather than the capability of the graphics card.
Regards,
Marty