T43 DDR2 Memory question

[anthony]

With dual channel DDR2 memory, must both DIMMs be the same? My T43 shipped w/512. I had always planned to upgrade. Can I only add another 512? Or can I add a new 1GB plus the 512? Do they have to be the same brand?

TIA.

[mdntridr]

if you want to use the DDR functionality, then yes, they must be identical in size, timing, etc, but not necessarily the same brand. Otherwise you can put in whatever size you like and it will work just fine in non-DDR mode

[jd2020]

I have a T43 which I added 512MB to the factory 512MB. How can you tell if you're getting the Dual Channel advantage and what exactly is the improvement doing? Thanks.

[boilermakerinatl]

OK, stupid question here. DDR is new to me. To take advantage of DDR do you have to have 2 DIMM's? (ie. for 1GB of memory is it better to have 1 x 1gb DIMM of 2 X 512mb DIMM's?

[jd2020]

Yes, that's how I understand it. 2x 512MB chips would take advantage of dual channnel technology, 1x 1GB would not.

Here's a "white paper" with details: http://www.kingston.com/newtech/MKF_520 ... epaper.pdf

[anthony]

Click Here for more than you ever wanted to know.

And there's this FAQ.

Ay Caramba!

[seraphsf]

I have a (quite lovely brand new) T42, which came with 256 Mb of DDR -- not DDR2 -- installed. I added a 1 Gb DDR stick.

I assume that DDR, unlike DDR2, does NOT need the memory sticks paired? Or should I consider changing my configuration?

Thanks...

[c333]

From my understanding DDR2 is a major upgrade from DDR. Both DDR and DDR2 have a feature called dual channel, which comes into play when two memory sticks are installed (in a compatable mobo) and both are the same size (many people recommend matching the brands/chips too). Dual channel adds 3%-5% performance compared to the same memory in a mobo that does not support dual channel. Don't confuse "Double-data-rate" memory to memory in a "dual-channel" configuration.

[emorphien]

DDR2 is not a major upgrade from DDR yet. Going from the 333DDR to the 533 DDR2 has some gains but the higher latency of DDR2 negates it in some applications.

DDR means that the rise and fall of every clock is utilized, it has nothing to do with dual channel. You can use DDR memory with just one stick.

Someone already posted a link on what dual channel does for you.