Not all i5 CPU's are Quad Core, some are Dual Core. Yours is clearly 4 core (quad core), so 4 logical cores. Not sure aboutm your core speeds, my Core i3 2100 runs at stock 3.1GHz but my CPU utlization is different on each core depending on what I'm doing, as I type my CPU utilization is 12% on Core 1 and 4% on core 2. They should run at differnet speeds depending on wat application/program they are running, I think.