Is more RAM always better?

[jebspring]

I recently bought 2 sticks of PC3200 512mb RAM prevously having two sticks of 256mb PC2100 RAM. I thought I had four memory slots but it turns out I only have three. My original plan was to install all four chips for a total of 1.5 gigs at PC2100 speed. But, now that I see I oly have 3 slots is it better to run 1mb of PC3200 in dual channel mode or 1.25gigs in PC2100 single channel mode? Will the extram 256MB ake up for the slower speed? Any help is appreciated.

 

[Fern]

Hi jebspring and Welcome to the Forums!

To get a decent answer, wouldn't hurt to list specs. At least what mobo you're talking about.

Fern

 

[Shooters]

Memory capacity and memory speed have different effects on system performance depending on what's holding you back more. Thinking that having an excess of one will "make up" for lack of the other isn't right.

That being said, if you install only the PC3200 do you intend on running it at PC3200 speeds or PC2100? And if you do run at PC3200 are you going to try and up your FSB to match it?...because if you don't then the upgrade will be pretty worthless.

By the way, if you run three modules, the two in the dual channel slots will still run in dual channel mode.

1GB of RAM is a lot, so if I were you I would just run the two PC3200 modules and play with the FSB to get it as high as possible to match the memory speed.

 

[TastesLikeChicken]

In most cases you won't see any real world benefit running dual-channel v. single-channel. One of the few times there will be a benefit is fi you have an IGP chipset and you are using the integrated graphics.

 

[Shooters]

Originally posted by: TastesLikeChicken
In most cases you won't see any real world benefit running dual-channel v. single-channel. One of the few times there will be a benefit is fi you have an IGP chipset and you are using the integrated graphics.

:thumbsup: Good point worth mentioning

 

[jebspring]

I have the MSI K7N2 Delta motherboard, it can use up to DDR 400 RAM, so if I were using only the two PC3200 sticks I would run them at Dual channel at 400. I didn't realize that the two sticks would still run in dual channel if you had a third one in. But, won't it default to the slowest memory you have? So my configuration would be running 1 gig in dual channel PC2100 speed and 256mb in single channel PC2100 speed if all thre sticks are installed? Correct me if I'm wrong.

 

[jebspring]

Oh, and I don't have integrated graphics. I'm using a geforce 6800 128mb and integrated sound. Thanks for all the help.

 

[jvarszegi]

Originally posted by: jebspring
I have the MSI K7N2 Delta motherboard, it can use up to DDR 400 RAM, so if I were using only the two PC3200 sticks I would run them at Dual channel at 400. I didn't realize that the two sticks would still run in dual channel if you had a third one in. But, won't it default to the slowest memory you have? So my configuration would be running 1 gig in dual channel PC2100 speed and 256mb in single channel PC2100 speed if all thre sticks are installed? Correct me if I'm wrong.

I'm pretty sure you're right, although others are more qualified than I to answer your question. If that is the case, I'd leave the extra stick off. The extra 256 megs will only be useful in cases when you exhaust a gig of memory; unless you specifically know that some of your applications will do that (in which case you'd be better off with even more memory), I wouldn't incur the performance hit for nothing.

 

[chocoruacal]

Run the RAM synch with your FSB. If you're using a 133mhz FSB chip, then running the RAM at 200x2=400mhz isn't going to make any difference; you can fill all three slots and run at 133x2=266mhz.

EDIT: and to answer the title of the thread, no, in certain applications running more RAM could hinder performance.

 

[uOpt]

Some older PC couldn't L2 cache all the RAM you could plug in.

Some/most current-generation AMD64 mainboards (both 754 and 939) cannot run DDR400 if you fill all memory slots, at least according to the spec. Some mainboard vendors give it to you anyway.

Otherwise, more RAM should never make things slower. However, not much faster either once you have enough.

 

[Fern]

Originally posted by: Shooters

Originally posted by: TastesLikeChicken
In most cases you won't see any real world benefit running dual-channel v. single-channel. One of the few times there will be a benefit is fi you have an IGP chipset and you are using the integrated graphics.

:thumbsup: Good point worth mentioning

Yeah, but only for AMD systems. Pentium systems benefit a great deal from DC.

But since he's posted back with his mobo, we now know he's got an AMD NF2 system.

 

[slash196]

Just put in the gig of PC-3200. Downclocking to PC-2100 will hurt your performance, and you don't really need more than a gig at this point.

 

[TastesLikeChicken]

Originally posted by: jebspring
I have the MSI K7N2 Delta motherboard, it can use up to DDR 400 RAM, so if I were using only the two PC3200 sticks I would run them at Dual channel at 400. I didn't realize that the two sticks would still run in dual channel if you had a third one in. But, won't it default to the slowest memory you have? So my configuration would be running 1 gig in dual channel PC2100 speed and 256mb in single channel PC2100 speed if all thre sticks are installed? Correct me if I'm wrong.

What FSB are you curerntly running at? iirc, PC2100 is rated for 133 (266 DDR). Is your processor unlocked so you can tweak the multiplier?

If you're currently running your ram at 266 or 333 (SOME PC2100 will do 333 easily) then you would very well see a small perfermoance boost by cranking up your FSB to 200 (400 DDR), However, if your processor is locked and is made for running at 266 or 333 you could have problems getting it running since it'll be overclocked and out of spec running at the higher FSB. That depends on a few different factors, but there are some potential issues. Let us know your system specs and we can help you out better with this.

And you are correct. The top end you can get out of your FSB will be limited by the slowest ram in your system. If your PC2100 can do 333 max, then your DDR400 is going to be limited to that as well so long as you've got them all installed together.

 

[TastesLikeChicken]

Originally posted by: Fern

Originally posted by: Shooters

Originally posted by: TastesLikeChicken
In most cases you won't see any real world benefit running dual-channel v. single-channel. One of the few times there will be a benefit is fi you have an IGP chipset and you are using the integrated graphics.

:thumbsup: Good point worth mentioning

Yeah, but only for AMD systems. Pentium systems benefit a great deal from DC.

But since he's posted back with his mobo, we now know he's got an AMD NF2 system.

People still buy Pentiums?

:shocked:

j/k

 

[Fern]

Originally posted by: jebspring
I have the MSI K7N2 Delta motherboard, it can use up to DDR 400 RAM, so if I were using only the two PC3200 sticks I would run them at Dual channel at 400. I didn't realize that the two sticks would still run in dual channel if you had a third one in. But, won't it default to the slowest memory you have? So my configuration would be running 1 gig in dual channel PC2100 speed and 256mb in single channel PC2100 speed if all thre sticks are installed? Correct me if I'm wrong.

I don't see anyway to use the PC2100 efficiently. You don't say what cpu you have, whether it's a 133, 166 or 200 mhz.

Anyway, it depends on what slots you install them in. If you're gonna use 3 sticks in an NF2 mobo, ideally you want 2 smaller (like 256MB) and one double the size- 512MB.

IIRC, the two smaller sticks go in slot 1 & 2, with the larger stick in slot 3. The sticks in slot 1 & 2 work together (thus combining for 512MB) and work in DC with the larger stick in slot 3. So, in effect you end up with two 512MB's working in DC (and in Balance).

Say you have three sticks the same size- 256MB. The two in Slot 1 & 2 will work together to be 512MB, against the slot 3 stick of 256MB. Although they are DC mode, only 256MB of the two sticks in slot 1 & 2 can work in DC mode with 256 MB stick in slot 3. The "extra" 256MB left over from the first 2 sticks isn't used in DC but is picked-up and used by the memory controller. It's unbalanced and not efficient. Can't say what the hit to performance is as I've never tried an ackward/unbalanced combo.

If it were me, I'd just run the two sticks of 512MB (each, for a total of 1 gig) in DC and sell the PC2100.


Fern

 

[Philippine Mango]

Fern is right, I heard memory performance about 1GB will hurt you a lot! Its pretty dumb that it does but thats how it is! So like he said stick those two 512MB DIMMS and sell the old ones! Now would be a good time to overclock that puppy since you have faster memory!

 

[VirtualLarry]

Originally posted by: Fern
I don't see anyway to use the PC2100 efficiently. You don't say what cpu you have, whether it's a 133, 166 or 200 mhz. If it were me, I'd just run the two sticks of 512MB (each, for a total of 1 gig) in DC and sell the PC2100.

Therein lies the crux of the delimma. 20% more memory in total, in exchange for potentially 33% lower clock-rates.

To the OP: the AMD K7 is most efficient running at sync FSB speeds with memory, and performance on many memory-intensive apps (such as WinRAR) scale with FSB speeds. OTOH, unless you are using onboard gfx, dual-channel does almost nothing for you on the AMD platform. If you CPU will run at a 200Mhz FSB, then I would personally probably just throw the two 512MB PC3200's in there, and run it that way, not for the DC, but for the FSB speed. If your CPU is only 133Mhz FSB, then unless you had a pressing need for the other DIMM (another older 533Mhz-FSB P4 to throw the pair into), I would put it into the AMD system, it would still give you some improvement, although more memory gives diminishing returns after you have "enough", and 1GB is usually that point for most users these days. If you CPU runs at 166Mhz FSB, then the question is, will the PC2100 (133Mhz) OC to 166Mhz, and do so stably/safely, especially in the presence of all three DIMM slots filled? I would take the risk only if I knew that 1.25GB of RAM would be of some benefit over 1GB. (Say, if you were doing imaging work or video-editing, more RAM is always good for those.)

Another question, is whether or not the existing or the new memory is double-sided or single-sided. Although there are three slots, I seem to recall a limitation that you can't fill them all with double-sided DIMMs; there is probably a limit of 4 "ranks" on the chipset, which means a limit of two double-sided or two single-sided and one double-sided DIMM. Plus, there is the slight issue of whether or not mixing slightly-different memory technology might cause compatibility issues.

On the whole, there would be much less hassle just putting the pair of 512MB DIMMs in, I think, because that should work whether or not they are double-sided or single-sided. So in the end, I agree with Fern's assessment of the situation.

 

[Googer]

there is a noticeable differance between 1gigbyte and 2GB of ram. It all depends on how its configured. Four sticks of 512mb is slower than 2sticks of 1gb. your best bet is to find two sitick of 2gb and set it to cas2.5 or2

 

[Andres3605]

he never mentioned 4 sticks of 512 neither 1 gb sticks, just leave the 2*512 and take the 256 out, anyways you had 512 before, now you have double that and better speed.

 

[zerocool84]

well i found a pretty noticeable improvement when going from 512 d/c to 1gig d/c in games in a multitasking. im not saying it will be the same for everyone but i found things to be much snappier in starting up and switching programs and also a noticeable difference in games also. hl2 loved my 1gig

 

[Googer]

fewer sticks of higher capcity means lower latency and = better performance



Adding memory to the 3rd slot makes your system run in single channel mode at higher latency

 

[jebspring]

Well, my CPU is currently only a 133mhz FSB but I'm in the process of upgrading to one with a 166 FSB. Until that time I think I'll keep all 1.25gigs in but when I get the new processor I'll switch to the two PC3200 sticks so that I can increase to that speed without problems.

 

[Googer]

j

 

[Googer]

As a general rule of thumb MORE IS ALMOST ALWAYS BETTER WHEN IT COMES TO COMPUTERS

 

[VirtualLarry]

Originally posted by: jebspring
Well, my CPU is currently only a 133mhz FSB but I'm in the process of upgrading to one with a 166 FSB. Until that time I think I'll keep all 1.25gigs in but when I get the new processor I'll switch to the two PC3200 sticks so that I can increase to that speed without problems.

I would do an extended (overnight) run of Memtest86+ on that RAM with it all installed, just to make sure that it is stable, and then Prime95 too after Windows is running, and double-check the mobo manual on the whole double-sided/single-sided thing regarding the DIMM slots, just to be on the safe side. But that sounds like a plan, Windows' will be able to use more RAM for a disk-cache at least.