Ok, so i was trying this Heaving benchmark (i know its DX11 Card Oriented, but just for the sake of benchmarking and considering changing settings if no harm)

the EVGA GTX 285 FTW product page when compared to others, it says it has the highest Ram Speed: 2646Mhz (effective)

in the Prescision Application, the The Ram Clock is set to 1323 Mhz, with max ( i didn't apply it ) of 2120 Mhz

now is the Ram speed is the Same As Ram clock ? (i think so ) and if so, i can set the Ram clock to the one specifid in the product page ? 2646Mhz

how with the precision tool max is 2120 Mhz ?

Precision tool shows you i/o clock, which is 1323 Mhz.
DDR allows 2 data transfers per clock cycle, thus 2646 megatransfers per second.

A bit off topic but I think system DDR3 has i/o bus clocked at x4 of memory DRAM cell clock.
Say memory cell clock is 200 Mhz, i/o bus is at 800 Mhz and you get 1600 megatransfers per sec, thus DDR3-1600

Hmmm good point. That's just how I had it explained to me when I asked the same question a long time ago.. probably when DDR3 wasn't commonplace.

Anyone care to enlighten us?

Thanks    So I was sort of correct, just a little confuzzled..