Intel i3 has two cores & it says each core process 2 thread.
I think Single core can handle 1 thread at one time.
SO in i3, two threads are handles in round robin fashion???

 

http://en.wikipedia.org/wiki/Hyper-threading

 

There are two sets of registers per core, but only one execution unit (ALU, FPU, etc), which can work with either register set.

 

1. I have read that current in processor is TDP=VI.
Normally voltage is around typical 1V around. So max current can go upto 65A???.

2. Is it safe to overclock processor with simple fan as which comes with CPU

 

you can over clock until the cows come home or until temps dont go above 90 degrees, whichever comes first.

 

1. I have read that current in processor is TDP=VI.
Normally voltage is around typical 1V around. So max current can go upto 65A???.

You're not going to see 65A going through any single transistor in the CPU, but because there are so many transistors, that is the total current going through the CPU.

2. Is it safe to overclock processor with simple fan as which comes with CPU

It depends on many factors: how much you're overclocking, how you're overclocking (whether overvolting or just using a different clock multiplier), how big your case is, how good the stock fan is, etc. The important thing is that the CPU temperature stays within specifications. One thing to think about is that PC manufacturers don't like wasting money. Therefore, they're not going to put in a much better CPU fan than needed, which means that while you may have some cushion, you probably don't have much.

 

A stock fan/heatsink is NEVER good for any level of overclocking. Don't even try.

 

I overclocked my Q8200 processor from 2.33GHz to 2.66GHz with the boxed heatsink without any trouble.