You need to limit the number of CPU threads with genproclimit=4 or whatever number of cores you have to spare.
Then I wonder: what is this setting: minermemory=2. Gb?

But memory also matters, right? I have two Win7 computers with identical setup and similar configs:

Computer 1: 4 CPU cores, 16Gb memory, 3.2Gb used; mining with 2 cores
Computer 2: 6 CPU cores, 16Gb memory, 4.3Gb used; mining with 4 cores

Computer 1 yields nearly twice as much ERC as computer 2 with only half the number of cores!