4x 512 single sided vs 2x 1gb or 2x 512 double?

Hey,

I'm wondering if anyone has done research into single-sided overclocking potential. Will 4x 512s tax the memory controller more than 2x double-sided 1gig sticks with the same chips (Micron 5b D)? Or will 2x double-sided overclock more highly than 4x single-sided? It's the same number of chips/sides, however lower density and filling fewer slots.

Basically, I'm building a new rig with an Opteron S939 on a DFI Ultra-D, and am curious whether my choice of module (the single-sided 5b D) will adversely affect my overclocking potential due to inherent limits of the on-chip memory controller of the opteron.

On a related note, how high can those Opterons generally get their HTT? I'm also hoping I didn't limit my o/c potential by getting a 144 .

Hopefully I can get some answers.

Thanks!

i'd really like to know the answer, too. good question

Using 4 single sided dimms would appear to stress the mem ctrl more than 2 double sided sticks. Page 177 of this AMD datasheet PDF rates (apparently) Winchester capable of:

2 x DS @ DDR400 1T
and
4 x SS @ DDR333 1T or DDR400 2T

E-revision mem ctrls might be able to do 4 x SS @ DDR400 1T.

1GB x 2 is better than 512MB x 4, at least, 512MB x 4 is not good for cooling, too many stick put together...

As far as I know, E6 controllers have no problem running the 4x SS at DDR400 1T. However, the thing I DON'T know is how it will handle overclocking overhead. It shouldn't adversely affect the HTT possibilities, I wouldn't think, but it might affect the RAM's abilities itself.

Basically, what I was curious about was whether anyone had done any definitive testing. If not, I can do the 4x SS vs 2x SS vs 2x DS 512 comparison when my DFI + opteron arrive, but I have no 1gb sticks to play with. Also, while I'm decently handy, I'm nowhere near as much of an expert as some of the members here, which is why I ask such things.

So, if you have any numbers you could toss out, links, people I should get in touch with etc., please let me know.

This is an interesting question, but I have never seen anyone try, and if you do so, I'd love to see the results. I would still wager that there is only a very small likelihood that you will be able to run 1T, but even if not, it won't be very bad. You shouldn't be limiting your overclock at all by getting a 144. HTT's generally aren't a problem well past 300MHz.

I have run 4x256 HyperX which were single sided sticks on a winchester. It was able to run them at 400MHz but only at 1t. I have no idea if the Venice would do any better, but it's certainly possible.

Well, here's an update.

I have learned that the DFI is a PITA to get running with 4 sticks in it. In fact, I'm about to reboot for the umpteenth time to mess w/ all the alpha timings to see if I can get it to load windows with four sticks in. All four sticks are good, it's just...silly.

So, in conclusion, I would recommend sticking to gig sticks.

Oh, by the way - http://www.dfi-street.com/forum/showthread.php?p=313063#post313063 is my thread regarding the issue. If any of you have ideas (here's lookin' at you, oh crucial man, eclipse ), feel free to either post 'em here or there.

Well,there will be a hit using SS vs DS. I would expect better performance with fewer sticks/sides.