Does DDRII memory need to be installed in pairs?

[BLACK KNIGHT]

Haven't been keeping up with hardware lately. Was thinking of building a new PC soon. Not sure if DDRII memory needs to be installed in pairs or if I can just run 1 stick?

[knight0334]

Its not upto the type of memory, but to the type of CPU and chipset.

Athlon 64's in either S939 or AM2 are dual channel = two sticks.
Core 2 Duo chipsets are supposed to be dual channel(2x sticks), but there are a couple out that are single channel.


Figure on getting (2) exact matching sticks no matter what you do.

[cauzomb]

DDR2 will still run with one stick, but to take advantage of "dual channel" It's good to get a matched set, If it doesn't say "dual channel" on the box with two sticks, it might not work in dual channel mode. "dual channel mode" is related to memory bandwithd.. If two matched sticks of ram are used, they can be addressed simultaniously by the memory controller, instead of one at a time. Supposed to "double" your memory bandwidth.. If you buy one now, and another one later, even if it's the same product code, there may be MFG differences, such as the type of memory chips used, or different timings that might not allow it to run in dual channel mode. Dual channel mode boards are flexible enough to adjust the memory speed, as long as the memory size is the same for each stick. The board will apply the timings and mhz of the slower stick to the faster stick, so that it will still opperated in dual channel mode, but there's no garanty that it will work, so it's best to buy a matched "dual channel" kit right off the bat.

On some newer motherboard chipsets there is something for DDR2 called "SLI"~probly for marketing reasons.. It doesn't do anything "performance" wise; The SLI-Memory thing is actually called EPP~ short for "Enhanced Performance Profiles"

SLI or EPP with the right chipset and bios, will allow more of the timing info and voltage settings to be changed, to help acheive a stable overclock.

Using more than two sticks on a board that supports the "sli" memory option will revert the chipset/bios into displaying/allowing changes to fewer of the memory timing options.

[BLACK KNIGHT]

Well if I decide to build a new PC I'm gonna go with an AM2 dual core processor so it sounds like I should just get one of those memory kits that come with 2 sticks.