Core 2 duo is dual core. And before that was core duo which was dual core too...

There are Celeron dual core processors today. However, just because you have Celeron processor, it does not mean your Celeron processor is a dual core processor. The easiest way to tell is to look at the Intel sticker on your computer. If it says "Dual Core," then it is dual core. If it does NOT say "Dual Core," then it is not dual core.

difference between dual core and core i3

sempron is not a dual core processor.

Dual core represents two processors in a single system.Speed will be more in dual core systems.