RAM More or Less?

[Spatula]

According to my Mobo doco, the more sticks of DDR RAM i put in it the slower the clock speed that will be used. It has a matrix of all possible combinations of sizes in all of the 3 182 pin slots. From what it appears to say, i can have 1 slot full and get the full DDR400/3200. As soon as i add a 2nd it drops to DDR320/2800, and the 4rd takes it down to DDR200/1600.
So it seems there's a trade-off between each memory modules clocked speed and the total amount of available RAM.

My MOBO is a Assus K8n-e.

So, my question is would 3 sticks (which would be clocked at DDR200) give me the same effective throughput as 2 of same total memory (clocked at DDR400) sticks? Eg am i better to less of bigger sticks or more of normal sized sticks?

My guess is its all the same really, as in the 3 module setup, although each chip is clocked at 1/2 the speed, the MOBO can access more modules per cycle, giving me the same performance. Or have i oversimplified it? I guess even at half the effective data rate, more memory would more than make up for the loss of data rate in performance tho.

[Krusty]

The slower ram isn't too much of an issue, unless you go down to DDR200 and slower. Then you're going to feel it. It will just be more of a bottleneck for system performance.

I think that's just peculiar to that mobo, because I've heard that before about that model. If you have any money, maybe just replace the mobo and keep all other parts?

Just dealing with the RAM alone, I'd say it's definitely worth it (in this case) to have 2 sticks intead of 3. However, if you already have 3 sticks of RAM, and you can find an insta-swap mobo that has all the capabilities you have now, it would probably only cost about as much as the new stick of RAM would.

Might be better (in the long run, and for performance) to just swap out motherboards.

Barring that, do it so you have 2 sticks only.

[Spatula]

Ok, thanks for that. So the under-clocking is particular to my MOBO and not to all of its generation? Also my mobo doesnt do dual-channel. So maybe its better to swap it out? I dont really want to, as im on a tight budget for now.

I currently have 1x512Mb DoubleSided CAS 3 stick in the MOBO. I just purchased a same spec 1 Gig stick. So im hoping it will work with both the 512 and the 1 gig in it. If it dont, i can pull the 512 and think about getting another 1 gig at some point.

[Krusty]

I'm not sure about mobos of that "era", I've only been looking at more recent ones lately. However most of the ones I've seen don't have that problem. As for dual channel, you often find mobos with 3 banks don't support it (you need an even number of banks). I don't use dual channel. When I had 1.5BG (1GB and 512MB) I ran in single channel mode, and it was still good. What annoyed me is that my DDR 400 was forced to run at 333MHz because my CPU's FSB was only 533MHz. That's a limitation with the mobo I used to have. My current mobo allows me to set DDR400 speeds and keep 533FSB (auto detected, not overclocked in any way)

[Wardog]

Spat

With 2 sticks of single sided DDR400 you will get DDR400 in Dimms 1 & 2. Only if the ram is single sided. With 2 sticks Double sided DDR400 in Dimm 1 & 2 your board will run at DDR333. But you can mix double sided & single sided ram in Dimm 1 & 2 and get it running at DDR400.

My last AMD setup was a K6-2 500 so i am outa touch with AMDs. But i suspect that the Nforce3 handle ram with the AMD memory controller.

And to answer the 3 sticks at DDR200, i see the board, again depend on the ram you have (sigle sided or double sisded) will runn 3 at DDR333 or DDR200. And yes the timings and latancey will be lower and therefore could be very close performance to the DDR400 setup.

With the older boards you had to put mismatched size ram in a certain way, Dimm 1 for the larger stick and Dimm 2 for the smaller stick or the board would'nt even boot up.
Download & install CPU-Z and find out what kind of ram you have, it will also tell you what speeds and timing the sticks have, then try to pick up the same brand, although with the older boards i had no problems mixing different brands.

Dog out.

[Spatula]

Yer, that sounds like it Dog. the 512 i got is just a crappy budget stick CAS 3, double-sided, non ECC, non buffered. The new 1 gig stick is the same type/spec.

Say, i aint seen ya round much this tour in the MA - what's up?

[Schutt]

I checked the manual that ASUS provides for your motherboard.

On some places of the ASUS web page it says your motherboard supports dual channel ram,if so, then when you have 2 sticks installed it should say at boot that it uses dual channel ram.

As wardog pointed out with 2 double sided ram you will get DDR333 "supported". That is not only due to the motherboard but also due to the fact that the AMD processors have RAM controller on the processor, which wasnt able to drive 4 DIMMS at full speed officially, might be a similar issue with 2 double sided for 754 processors.

With the newer Athlon64 that limitation is lifted, I am unsure if newer socket 754 processors have a more powerfull ram controller as well and are able to drive the ram faster, i think it came with the "E6" revision.
Also you can manually select a higher ram speed if you want to take the risk, but it might lead to crashes... which can shred data or do more damage.

If you gain dual channel mode with the second module both together will be faster at 333 than your old module at 400. There are some hardware tools (i use SiSoft Sandra) that will measure your ram throughput. So you can install the tool, check ram speed with your current config (throughput), upgrade and then check again.

You can not use ram modules that are bigger than 1GB, at least according to the manual. And with 1.5GB you are better of than with 1GB, eaven if your board does not use dual channel and runs the ram at 333. I would stay with that motherboard, the work changing the motherboard is not worth the gain if you stay with the same CPU and graphic card.

[Kev367th]

Some early boards can still run dual channel even with 3 sticks of RAM.

The knack to it -

The channel with the single stick of RAM - Must equal the size of the channel with two sticks in.

So if you have 2 sticks of 256Mb in one channel, the other must have a single 512Mb stick in it.

Two 512Mb sticks, the other channel must contain a 1Gb stick.

Etc, etc ,etc.

[Kermit de frog]

I had a problem like this with a mobo once.  Instead of buying a huge stick of ram and throwing away a stick of old ram just to increase the memory size and keep the speed the same, I bought a mobo that was only less than the cost of a cheap stick of ram and had all the features of my old mobo and it allowed me to keep all my memory sticks.

So, replace the mobo and get yourself a mobo that gives you what you want.