The reason behind why most games built with the U3 platform doesn’t use more than 2 cores (or 3) is not because the engine itself is incapable of doing so. It’s even hardly relevant because core assignment is the sole area of the OS’s scheduler. You could “force” some threads on your game to only use certain cores by invoking certain functions like SetThreadAffinityMask() in Unreal engine, but this is mostly used the other way around (forcing threads to Buy Blade And Soul Gold), and this function has been there since the old days of Unreal engine.
Most modern games aren’t even using U3 anymore since U4 were released a while ago. And some even switched to Unity or their own custom engine. Developers in the old age of U3 assumes that most of their users would be people running with dual core processors, hence the number of threads are limited within that constraint.
There are some games that’s patched to make use of 4 and even more logical cores that’s built on U3. Most notably is Unreal Tournament 3 or something like AA:PG, Bioshock, Lost Planet, Rainbow Six, all were built with U3 or lower.
Why I said it only uses 2 cores (I’m talking about specific case for BnS) is because it will use the computing power of the equivalent of 2 cores: 2 core – 100% usage, 4 core – 50% usage, 8 core – 25% usage etc. I don’t know the technical mumbo-jumbo and I don’t know where you were getting at. It doesn’t matter how the OS distributes the workload, it won’t change the fact that your CPU won’t be fully utilized.
BnS will never make use (of the equivalent of) more than 2 cores – and I really hope I am proven wrong. This is the main reason why we get this crappy performance.
BnS has worse performance than Tera. Back when I played CN, luring an entire room of mobs like the 45 spider dungeon would make the game freeze until the initial attack by the party members ended. Tera eventually added mass grindable mobs in ow during the gunner patch, and it was smooth with Blade And Soul Power leveling. It was smooth enough that I could dual client to finish 2 character’s dailies at once. Considering everything in BnS is instanced, it just makes it worse in comparison to Tera which has seamless ow and a lot better graphics.