Dual channel plus extra?

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lukeh182

Gawd
Joined
Jan 17, 2003
Messages
616
i looked in the memory FAQ but couldn't kind what i was looking for so if it's there i'm sorry that i missed it. if i buy 2x256 corsair xms now and in a few months i decide to get a single stick of 512 will that screw up dual channel or will it still work correctly? please don't post if you THINK that you know i would like a definite answer. not to be rude or anything:p
 
Actually he'd be better off buying a 512 stick now, and another later, then run 1GB in dual channel. DC doesn't help AMD based systems much though, so you won't 'lose' much by not running DC now...

edit: err, maybe that's what your were saying...
 
Originally posted by Phoenix86
Hmm, ok I think the answer is here. http://www.hardforum.com/showthread.php?s=&threadid=707289

;)
Click to expand...

if you'll see in my first post, i tried to find the answer there but i had some trouble so i was hoping someone could help me out.

Actually he'd be better off buying a 512 stick now, and another later, then run 1GB in dual channel.
Click to expand...

i thought about doing it that way, but if you don't have "matched" pair you are less likely to get the maximum performance out of DC, but i've heard (asyou said in your post) that AMD doesn't take DC as well so maybe it really doesn't matter!:rolleyes: and some people say it doesn't matter if the pair of RAM aren't matched. so who do you trust?:confused: sometimes i wonder about this computer stuff?! lol

decisions decisions
 
As far as buying memory for a DC setup at different times, it could be a little risky. However people do run non matched pairs w/o errors. What I would do is just buy a good name brand, and make sure to get he same model/speed when you get your second chip.

"Q: How do I use Dual Channel?

Dual Channel requires at least two modules for operation. It is recommended that the modules you use be of the same size, speed, arrangement etc. Dual Channel is optional on the orginal nforce2 motherboards and nforce2 ultra400. You can choose to run in single channel mode on these motherboards. (Nforce2 400 boards are singe-channel only).

Most dual channel capable nforce2 motherboards come with three slots. On these motherboards the first memory controller controls only the first slot (or the slot by itself), while the second memory controller controls the last two slots (which are usually closer together). Name them slots 1, 2 & 3 respectively. To implement Dual Channel, it is necessary to occupy the slot 1 (channel 0) and either one of the two slots that are closer together, slots 2 or 3 (channel 1) The entire config would be running in 128bit mode.

You can use three modules in Dual Channel Mode, by filling the third unoccupied slot. With three sticks, slots 1 remains as channel 0 while slot 2&3 become channel 1. To maintain 128-bit mode, with all three slots filled, each channel must have an equal amount of memory. For example, slots 1 should be filled with a 512Mb module, while slots 2 & 3 are populated 256Mb modules. If you were to use three modules of the same size, then only first two modules would be running in 128bit Dual Channel Mode. Example, using 3x 256Mb modules will have the first 512Mb running in 128bit Dual Channel mode, while the remaining 256Mb will be in 64-bit Single Channel mode.

Intel dual-channel systems are different. The have either two or four slots, and to run dual channel mode must have either one or two pairs of (hopefully) matching modules. Running three modules on a P4 system will force it to run in single channel mode, and is therefore to be avoided.

Consult your motherboard manual for instruction on exactly which slots exactly to use

Q: What is Matched or Certified Dual Channel Memory?

Companies like Corsair, Mushkin, OCZ, etc produce what they call "dual channel" memory, or Dual Channel Kits. These are sold in pairs, so for instance you might buy a 512MB or 2x256MB Dual Channel Kit, which consists of 2 sticks of 256MB DDR memory paired together by the manufacturer.

Companies don't just throw two sticks of RAM together to produce these kits, but they don't necessarily produce a totally different batch of RAM either. Testing or qualifying Dual Channel memory might involve something as simple as technicians booting up pairs of RAM in a Dual Channel motherboard and ensuring they work together under a set of conditions, or it could be more complicated, including so called "SPD" optimisations and even chip selection (we're inclined not to put much trust in any of those claims ). For your purposes, you should assume that Dual Channel memory is qualified through testing as all companies will claim that every pair of Dual Channel memory is tested prior to being packaged.


Q: Will Non-Dual Channel Matched RAM work in my nforce2 motherboard then?

It most certainly, will. As long as it fits the requirements of Dual Channel operation (two of the same types of memory, same size modules, speed, etc). Two modules of the same model/brand purchased from the same vendor at the same time is essentially as likely to work properly in a dual channel configuration as is a dual channel kit.

The ONLY thing you can lose by buying "single channel" memory for use in Dual Channel mode is that manufacturers may or may not provide support and replace your memory if it won't work in dual channel mode, whereas if Dual Channel memory fails to work in Dual Channel mode, the manufacturers will help you resolve the problem and possibly replace the memory to ensure proper Dual Channel operation.

There are instances of people using two different types of RAM together and have had no problems. You can't damage your motherboard or RAM just by trying to use two un-identical module in Dual Channel mode. But be advised that if the machine is unstable for any reason, it is entirely possible to corrupt your data upon operation of the machine. Mis-matched memory sticks in a dual channel configuration often produce unstable operation, so as with any new overlcocking or upgrading venture make sure you have adequate backups so you can recover from a data loss."

I clipped out the sections to read that pertain to your questions. Sorry I missed the line about you not finding it in the sticky.
 
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