i bought new laptop and using DDR2 ram.
by using CPU-Z software to check my ram, found that showing 333 MHZ DDR2,

how come my ram run at 333 mhz?

It might be caused by DDR doing something twice per clock cycle. So the effective speed is twice the real clock

DDR stands for Double Data Rate. DDR2 533 runs at 266.5 Mhz, DDR2 667 runs at 333.5 Mhz, DDR2 800 runs at 400 Mhz...

Your memory is running at DDR2 667 speed.

Actually your RAM is running at 333.3MHz, but its effective speed is 666.7MHz because it performs operations twice per clock.

EDIT: Such is how DDR RAM works, and it is perfectly normal.

EDIT2: Read the Memory sticky, it needs to be fixed up though due to the new forums different formating code.