(1)pre-caching with the second core.
(2)all other system OS tasks fit into the second core.
(3)on linux the encryption of the hard-drive fit into the other cores.
(4) NUMA effects Single-thread apps on multi socket systems the L3 cache of all cpus are used to cache the single threaded process.
(5) more ram over NUMA more ram means more speed if the working task is bigger.
(6) 4mb L2 cache vs 1mb L1 cache in the emulation.
A single socket system like the amd 8150 do have at maximum 32gb ram a dual socket g34 socket system do have 128gb ram with the same ram 8gb ram modules full loaded on all places.
its 32gb ram vs 128 gb ram and you can use this in a single "thread"
Same with the cache a opteron 6300 dualsocket system do have 32mb L3 cache useable over the numa architecture in a single thread.
A modern OS do have many threads this means the multi core system can handle all other threads this speed up the main used thread.