DDR, can you explain something...

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chevytrucknut

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Here's the specs off of my mobo:

"...provides 4 DIMM sockets using Dual Channel 184-pin DDR with a total capacity of up to 4GB. Supports DDR 266/333/400MHz Memory."

So if I'm buying memory, and i plan on getting somewhere around 2 gigs. I'm not sure which kind exactly to buy. By dual channel, what does that mean.

thanks
 
correct me if I'm wrong, but It means 2 slots on the motherboard are channel A, and the other 2 are channel B...

so if you had 2 sticks of ram, and put one in the first and third, you would be useing duel channels...
 
Well if you want 2 GB of DDR Ram which if you ask me isn't nessacary as nothing uses more than a GB but if you want 2 GB get 4 chips of 512MB DDR. With dual channel that means that 2 memory modules work together. So the main difference is more performence. You're probably thinking why not get 2 1GB chips. Well it's faster to get 4 512MB chips and put in dual channel and probably cheaper as well. But all i'd do is get 2 512MB chips put em in dual channel mode and then get another 2 512MB chips in the future when you need more! With the different mhz of memory that means how fast FSB the memory supports. The normal mhz is 266 which is how fast CPU's FSB is at stock speed but as soon as you start to overclock the CPU the memory needs to be overclocked as well so you need a faster RAM. SO only get RAM that has more than normal MHZ if you are planning to overclock otherwise save your money and get cheaper 266 MHZ RAM. If you think you might overclock in the future but you want 266 MHZ RAM you can put memory timings so the RAM can work slower but it won't be as good as having proper overclocking RAM. I think that pritty much covers it all! :D
 
WOW...suprisingly, that ACTUALLY made sense!

So does it have to say "Dual Channel" for it to work? Or will just a (2 x 512) work
 
2x 1 gb ram is better than 4 x 512. 4x 512 has a higher latency because the proc has to have an extra cycle to process through all the memory. Also many games now eat up at least a gig of ram so 2 gb is better for games and high level high gfx intensive programs
 
It does if the first channel ram sticks match each other and the second channel ram sticks match eachother
 
chevytrucknut said:
WOW...suprisingly, that ACTUALLY made sense!

It shouldn't have, because he's wrong.

First of all, 1GB of RAM isn't enough anymore for some games, so 2 GB is better. Second, don't get 4 x 512MB if you're planning on getting 2GB. 4 x 512MB will be slower, will consume more voltage, and will be an overall hassle. 2 x 1GB will be a little more expensive, but you should've been prepared for that if you're planning on 2 GB.

Now, if you have two identical sticks of RAM (same size, and preferably same manufacturer) then they will be running in Dual Channel. There is no such thing as "Dual-Channel RAM," that is simply a marketing tactic. Any two identical sticks of RAM, no matter what the size (as long as they are the same size) will run in Dual Channel. On your motherboard, there will be pairs of colored RAM slots (DIMMs). If you're using 2 sticks of RAM (recommended), then you need to put them in the same-colored slots for them to run in Dual Channel.

Running in Dual Channel gives each stick of RAM its own bandwidth, so it can talk freely, instead of being strangled. This gives a considerable performance boost.

As for Kahlos's MHz; The standard memory speed today is DDR400, which runs at 200MHz (DDR stands for Double Data Rate. DDR lets you send an instruction on the rise of the clock cycle as well as the fall of the clock cycle, effectively doubling what can be done with a given clockspeed. So though the clockspeed is 200MHz, it is EFFECTIVELY 400MHz, which is more accurately called DDR400). Your system bus (as far as Athlon 64s go) also runs at 200MHz. As standard, your memory runs with a 1:1 ratio with your system bus (HTT on Athlon 64s, FSB on Pentium 4s). So if your system bus is 200MHz, then your RAM is at 200MHz. As you raise your system bus, the memory's speed also increases (and the processor speed also increases). That is basically what overclocking is. You don't need higher-rated RAM (DDR500, DDR550, DDR600) to overclock since there is overclocking DDR400 RAM, and you can set a memory divider which lets your memory run at a lower frequency than the system bus, which allows you to overclock your CPU without stressing the RAM even a little bit.

Anything else?
 
yes, Flanker is right on this.
you can't run 4x512MB sticks in dual channel. motherboards only support dual channel for 2 of the 4 slots, which is the first and the third usually.
dual channel only works if you have 2 sticks, and they are in the right slots.
 
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