Ram usage advise (slots etc.)

[PerfectBlue]

Firstly this question i don't think it relates much to linux, but just wondering a question. I have 3 RAM slots, i ever though of just use one 512MB, but heard some people say it's better to use two 256MB, i'm wondering why and wondering whether is it true?

[mrBen]

Back in the old days of SIMM memory, you had to insert modules in pairs in order for it to work properly. AFAIK there is no reason to do the same with DIMMs - just leave it as it is (or buy a couple more 512Mb DIMMs and really enjoy yourself)

[mdwatts]

Whatever the max each slot will accept.

There is not use putting in i.e. three 128's in the 3 slots since if you want to add more memory, you will need to remove one of the 128's and then that one will be wasted.

I just built a pc for the gf and put in a single 512 in one of the 3 slots.

[PerfectBlue]

i agree with you guys, but do you know if a slot is insert with PC2700 256MB and i insert another slot with PC3200 512MB, will it cause me any problem? or i have to be consistent?

[mdwatts]

You should be ok though the ram will run at the slower speed.

I have often mixed PC66, PC100 and PC133.

[glussier]

use one 512MB, but heard some people say it's better to use two 256MB, i'm wondering why and wondering whether is it true?


This is true, if your motherboard is a dual-channel mobo. To benefit from the dual channel architecture, you need to install your memory sticks in pairs.

[PerfectBlue]

hm.......... any ideas how to find out whther i have a dual-channel mobo?

and i'm keen to know what does mdwatts' mean by the ram will run slow, what's the reason behind, thanks

[mdwatts]

Originally posted by PerfectBlue
hm.......... any ideas how to find out whther i have a dual-channel mobo?

and i'm keen to know what does mdwatts' mean by the ram will run slow, what's the reason behind, thanks

Motherboard manual or website.

I meant that if you combine a 2700 and 3200, both will run at the speed of the 2700.

[bwkaz]

The reason both will run at the speed of the 2700 is that the processor's memory bus requires it. If two different memory boards are running at two different speeds, the processor <--> memory bus will get all confused.

So the motherboard's memory controller is smart enough to run all memory boards at the same speed (at the highest that all of them support, in other words, here, PC2700, AKA DDR333). It will also drop the speed of the memory if the motherboard itself can't handle the higher speed -- so if you put only the PC3200 into a KT333 motherboard, you'd be running at PC2700, because that's all the faster that that motherboard's memory controller will run (unless the BIOS gives you overclocking options, but that doesn't count ;)).

[stiles]

Originally posted by PerfectBlue
hm.......... any ideas how to find out whther i have a dual-channel mobo?


If you have a E7205 or Nforce2 chipset you have a dual memory channel mobo (well thoes are the ones that I know of.