how do u tell the difference between 3.6ns & 5.5ns

[parasitegoth]

im just wondering how do u tell the difference between 5.5ns and 3.6ns what does it = in ram speed on videocards how do u figure it out on oem products

 

[Lord Evermore]

You have to look at the chips themselves. Some brands have the speed rating right on them, others use codes that you'd have to be able to look up.

 

[thorin]

Yup either look for a detailed review of the card in question (since they normally cover this information) or get the numbers off the chips and look it up online.

Thorin

 

[parasitegoth]

im just wondering say i want to buy a saphire 9100 64mb and say it;s clock is 250/230 or 230/200 what does that = in ns ram

 

[Lord Evermore]

Well, it doesn't definitively imply anything. You can run say 3.6ns memory at 200MHz if you want. If you just look at the MHz rating, you still don't know what actual nanosecond rating the chips have.

At any rate, you get the memory's MHz rating from the nanosecond rating by dividing 1000 by the ns. So 3.6ns memory is designed for use at 278MHz (556MHz DDR), but depending on what the manufacturer had in stock and decided would be most cost-effective, they may only clock it at 200MHz/400MHz even though the memory can go faster. (It's a well-known practice to use faster chips but clock them at lower speeds, because there's always a market for the lower speeds but it's not cost-effective to produce chips that physically can't handle faster speeds.)

To go the other way, divide 1000 by the memory speed, a 200MHz memory speed (400MHz DDR) means that the memory has to be no slower than 5ns (unless they factory overclock the memory for cost savings), but they could easily use 4ns chips, which would mean you could overclock the memory possibly as high as 250MHz.