I don’t really know what you’re trying to say either. No offense, though. Because usually when someone refers to “X game only uses 2 core on a quad or octacore processor” it literally means that. That is only 2 cores are being used out of the 4 or 8 physical cores the processor has Blade-Soul Gold. Which implies a bad optimization resulting from low thread uses on the codes/inefficient thread distribution under the assumption that the game’s going to be run on older spec’ed PC, or just plain bad coding.
When a game makes use of more cores, it means that the game’s optimized to make use of multiple cores. This is quite literally what multi-core optimization means. Because it means that there are multiple cores running and processing multiple threads at the same time, which is what made games performs better than those that aren’t. It does not matter the percentage distribution of the load. And having a game or a software consuming higher percentage of load on your CPU does not mean that the game’s better optimized, it just mean that the game consumes higher load when doing certain tasks in comparison to your core’s clock speed.
BnS is not really optimized to run on multiple cores, but it does run on multiple cores because the engine allows it to and the load distribution’s handled by your OS. That’s one of the reason why the performance is crappy on some cases. The game being built with U3 is only one of the main cause of why the performance is bad, there are a lot of new games which is released with U3 and run just fine with top end spec’ed PC. It’s just that the developers didn’t design the game to make use of the newer hardware and newer features and arguably uses the ‘wrong’ engine to build the game around.
You can’t really change “engines” mid way. Well you could, if the development team prepared to do so from the beginning. But it’s really really rare for a game or a software for that matter to undergo such changes with Blade & Soul Power leveling. Normally when people talk about ‘further optimization’, engine-wise it can be a new release/build for the U3 engine, or different lines of codes used to process a certain task, or splitting one tasks into more threads to distribute the load, or something else entirely.
An engine is like the your house’s foundation, you can improve your house, make additional terrace, new fences or windows, even a new garage, or a shiny new paint. But you can’t change the foundation.