It means that the CPU has 2 physical cores but can process 4 threads simultaneously through hyper threading or Simultaneous multithreading (SMT). In reality, one physical core can only truly run one thread at a time, but using hyper threading, the... read more
In reality, one physical core can only truly run one thread at a time, but using hyper threading, the CPU exploits the idle stages in the pipeline to process another thread. By doing this, it gives an illusion of a separate physical core to the OS. read more
A CPU core can basically be seen as a single processing unit. A two core CPU essentially has two seperate processing units, which are almost fully independent of eachother (CPU cache and main memory are shared between all cores). read more