What difference can a nanosecond make?

[ThreeDollarBill]

Upgrading my video card. Decided to go with the GeForce 3 Ti 200 series because of the great value and the overclocking potential.
I can get one of two cards. Either the VisionTek Xtasy 6564 or the MSI G3Ti200 Pro-"x" (not sure about the exact flavour, whichever is the cheapest, no-frills version).

I noticed though that (according to Tom's Hardware) the Xtasy comes with 5ns memory onboard while the MSI card comes with 4ns memory (assuming all MSI GF3 Ti 200 series cards come with 4ns memory).

Since the overclocking potential is what got me interested in the GF3 Ti 200, I'm wondering what impact a 1ns difference have on the top memory speed I'll able to achieve?

Thanks

 

[SlimHarpo]

5 ns memory is rated by the manufacturer to 200 MHz (1000ns/5ns), or 400 MHz "effective" ddr rate. 4ns memory is rated to 250 MHz, or 500 MHz "effective". There are plenty of other variables, like quality of construction, voltage, etc, but all else being equal the card with 4ns memory should go quite a bit higher.

 

[merlocka]

I'm wondering what impact a 1ns difference have on the top memory speed I'll able to achieve?

Well, it depends which nanosecond your talking about

In this case, the Visiontek comes with 5ns memory. This memory is rated for 1/5ns = 400MHz (DDR) operation
The MSI's 4ns memory is rated for 1/4ns = 500Mhz (DDR) operation

A couple of notes...

1) Manufacturers sometimes change the memory they install. Search forums to see what memory people are getting on their boards.
2) Overclocking results vary from batch to batch. In general it's a safe assumption that 4ns memory will overclock higher than 5ns memory, but YMMV.

 

[Jman13]

For what it's worth, my Visiontek reaches 530MHz memory speed without problems. I run it at around 500MHz just to be on the safe side. YMMV.