The end user/OS only sees 4 virtual cores.
virtual cores 0 and 1 belong to real physical core #0
Virtual cores 2 and 3 belong to real physical core #1
hence, your game is already optimized, as its using both
the real physical cores, via virtual ones 0 and 2.
Incase it was using 0 and 1, or 2 and 3 together, that wud be the non-optimized way of doing things.
PS:- Almost all modern OSes after 2008 can well aware and make the most efficient use of HT, so stop worrying about stuff like this, and enjoy ur gaming