Dual core confusion

Single core runs 1 task faster than dual core. Dual core runs 2 or more tasks faster than a single.

Could you please specify the CPU you saw, post a link maybe? LeoMatrix is wrong. A dual core will run a single task faster than a single core of the same clock speed, because a lot of programs these days are optimized to run on multiple threads (cores) at the same time.

I have no idea what that means. I have never seen cpu specs listed like that before.

I am really sorry this is a Mobile Phone processor it is this phoen here, http://www.pandawill.com/5s-android-23-os-smart-phone-3...

its an ARM11.

Those little guys can operate in a higher clocked performance mode or a lower clocked power efficient mode, depending upon hardware application. My guess is that those two speeds represent the official performance range of that chip. 650mhz being its high performance mode, 350mhz being power saving mode.