[Calindor]

Just a few questions on RAM....I'm sure everyone knows the more the better, but I'm wondering things about the amount on each stick. For example is it better to have 2x1gb sticks in dual channel, than 1 stick of 2gb. Is there a noticable difference between 4x512mb and 2x1gb?

[Howling]

i always thought that less sticks was better.. though I suck at explaining things... Imagine your CPU is an employer and money is power, and RAM is the employee.. would you rather pay 4 workers to do a job, or 2 workers? It's obvious, you'd want to pay 2 workers so you had more money for yourself - ie more power for yourself..

I explain it very badly, but that's always been my understanding of it.. hence I'm running 2x2gb sticks instead of 4x1gb sticks

[Typecast]

Howling said:

i always thought that less sticks was better.. though I suck at explaining things... Imagine your CPU is an employer and money is power, and RAM is the employee.. would you rather pay 4 workers to do a job, or 2 workers? It's obvious, you'd want to pay 2 workers so you had more money for yourself - ie more power for yourself..

I explain it very badly, but that's always been my understanding of it.. hence I'm running 2x2gb sticks instead of 4x1gb sticks

you can also look at it from a different angle.

Do you want to divide the workload on 4 workers or on 2 and make them work twice as hard?

but anyways I also use 2x 2 gig in my pc, never had any complaints.. honestly I dont think there is much of a difference.

[Celestin]

Err... correct me if I'm wrong... but I'm pretty sure you're both wrong.

The general idea is that the more RAM you have, the better. Just like the more cache you have, the better.

But the bigger your RAM, the more likely you are to miss and the more misses you can have. Misses are costly and can add up. This is especially bad if your data is nowhere in where you expect it to be because you have to have a whole bunch of misses before your computer even complains. You'll also need bigger lookup tables.

But who knows. Having more RAM probably just overpowers the damage misses do to your efficiency by reducing paging requirements ( once it is in RAM anyway ). Less paging is always a good thing.

The idea about splitting work among employees is... kinda right I guess. But a lot of that heat generation now is due to how much current is running through your RAM in order to efficiently double pump data on the very large modern buses. Plus there are tons of reasons why your computer would not evenly distribute load between four sticks. For example, if it wants contiguous blocks, the best and obvious solution is to dump it on one stick if possible. Or when your RAM starts to get fragmented, your computer is going to use the first appropriate slot that is available to stick whatever you need into, and if all of those slots happen to be on the first stick, then all of the data is going to go on the first stick. This is probably most true with worst fit RAM management.

This post has been edited by Celestin: 17 April 2008 - 02:53 PM

[Howling]

yes but the question is 4x512mb or 2x1gb sticks... not "is MOAR RAM BETTAR?" :p

[Celestin]

Howling said:

yes but the question is 4x512mb or 2x1gb sticks... not "is MOAR RAM BETTAR?" :p

I answered that question too.

2 x 1GB = more misses, but probably more even usage of RAM. Big lookup table.

4 x 512MB = less misses, but probably less even usage of RAM. Small lookup table.

Lookup tables don't matter as much as everybody uses set associative or better(?) lookup tables, but still could make a difference. In any case, I have no idea because this is how it's been drilled into me in terms of theory, but at the same time, programs don't just guess where data is.

This post has been edited by Celestin: 17 April 2008 - 03:00 PM

[Howling]

I misunderstood, my bad :)

[Kalean]

It's best to go with the smallest amount of memory as possible. take 2x1 of 4x512....It's definitely an interesting topic to discuss. But keep in mind the more sticks you have, the more voltage is needed in order to run a set of 4 sticks. In terms of overclocking, having 4 sticks can actually cause instability and hurt your OC..You'd get a less overclock, and running into a higher OC would only be more stable on a 2x? scenario. Do keep in mind if you have 1t command rate modules and have 4 of them, there is a chance you won't be able to run all 4 in a 1T command rate, you'd have to drop it to 2T to compensate for the extra modules which would actually hurt your overall performance.

It's a complicated matter...I understand what you guys are saying in terms of "it can spread the workload quicker"...But keep in mind these are dual channel...The workload would be split to two modules, not 4...For that you'd need quad channel in order to do so...Once the memory fills up on one, it would processor over to the other. That's how I believe the memory usage works, but not 100% sure since I never really sat and thought about how two setups of dual channel memory would work...

[Calindor]

Well afaik for dual channel ram, it only splits between 2 sticks...and the extra 2 do not get used unless the first 2 are full...like the way old ram used to work. Or does it evenly split the load between the 4 sticks?

nvm i started this post before the one above was made :(

[Kalean]

lol calindor, =P...Don't worry about it. But yes, dual channel means it utilizes two sets of memory at once...So having two setups of dual channel will result in still the same performance. But once one fills up, it'll utilize the second. That's how I believe it ends up working.....But triple channel is almost here with Nehalem =P...My board actually supports quad channel, but memory is just so expensive for this machine >_<.