DDR Memory....

[Szech]

I'll take an educated guess at this one. DDR technology sends data on both the rising and falling edges of the clock. Currently, RAM is built with gates that respond to only one. Therefore, current RAM would not be compatible. As for the Athlon mobos, I have no freaking idea how they do it, but it doesn't seem as though they have special RAM.

[Warthog]

DDR technology sends data on both the rising and falling edges of the clock

I thought that's what Rambus memory does? I don't know much about DDR memory because it's not really out yet, so I can't answer your question.

Warthog

[Ruahrc]

Here's how I understand it/my guess:

DDR Memory does basically double the RAM Rate. I'm pretty sure that's right.

About the modules though, special DDR memory will probably be needed to take advantage of the DDR function- but I'm guessing (and could be very wrong) that if you use standard memory it will just revert to a standard rate (sort of like using an ATA33 cable for an ATA66 drive)

Just my guess

Ruahrc

[gyoung]

I understand the DDR memory in the simplest form. Basically it doubles the rate of the RAM. Thus PC100 becomes DDR200 and PC133 becomes DDR266.

My question is this. Does that mean you can use standard PC100 memory and PC133 memory modules and that they just changed the interface? Or are they new types of modules?

I'm curious because when the new DDR mobos start showing up, am I going to have to buy new DDR RAM or can I use my existing RAM?

I'm guessing I'll have to buy new memory. Just a wild guess http://sysopt.earthweb.com/forum/wink.gif


[This message has been edited by gyoung (edited 07-31-2000).]

[truffeltje]

When you buy those mobo's for ddr ram you need to buy ddr-ram because ddr-ram uses more pins than sdram.
sdram = 168 pin dimm
ddr-ram = 184 pin dimm
prices for ddr-ram are
64MB will cost $86
128 MB will cost $170

Truffeltje

[Dputiger]

DDR-RAM will not be compatible with existing SDRAM and will cost only about 10% more. As to how it works:

A clock cycle is the amount of time it takes the CPU to do complete an operation. Because computers are binary that means that a clock cycle is either at 0 or 1--meaning it has, or has not completed its next operation. When the computer is changing from 0 to 1 its called the rising edge of the clock cycle--when its changing from 1 to 0 this is the falling edge of the clock cycle. In the past, computers only transmitted data to RAM at the rising edge of the cycle. DDR RAM will allow them to transmit on both the rising and the falling edge.

Hopefully I got this right and it makes sense.

[gyoung]

Excellent responses! I don't really need to know the complex details, but that summary makes it very simple. Its good to know... Now I will hold off on putting together that new PC.

Thanks!

http://sysopt.earthweb.com/forum/smile.gif

[This message has been edited by gyoung (edited 08-01-2000).]

[SysOpt]

These should help:
http://sysopt.earthweb.com/articles/memory/index.html http://sysopt.earthweb.com/articles/samurai/index.html

It pays to visit the sysopt home page now and then.