2x1gb or 4x512mb- can i run dual channel?

[trOver]

hi all, i need some help with memory...

im building a new rig soon, and i dont have the budget to go to 2gb when i first buy, so im stuck with 1gb. i want dual channal while i run my 1gb, so im looking at 2x512. the memory speed will be 800mhz and be with an evga 680i mobo, and an e6600. i know that memory can be picky when it comes to running in dual channal. my question is can i run 4x512mb in 2 dual channel setups when i upgrade later? or would you reccomend getting a single 1gb stick and trying to get one that will work in dual channal with it later when i upgrade? thx

 

[pkme2]

Get 2 sticks 1GB RAM.
So get 1 now, and get another for dual channel later.
Smart move.

 

[bamacre]

No, get the 4x512MB. That way, you are in dual channel mode with 1GB (2x512MB), then later as well with 2GB (4x512MB). Dual channel only needs your memory installed in pairs. You can even run 2X1GB and 2X512MB (total 3GB) in dual channel.

 

[Ruptga]

I've heard of some boards not liking four sticks of ram, it drops it down a speed notch. But that may only be for older boards, don't quote me on it.

 

[oynaz]

I run 2x512 and 2x256 with no problems at all. My rig is rock-stable

 

[trOver]

so do you think the new evga board would knock down the speed on 4x512?

 

[Fike]

It is best to try to match memory manufacturers and specs. Some boards are finnicky about mismatched memory. I have struggled through that myself when I tried to match 3 different 512 sticks bought at different times. I had to pull back the timing to the lowest common denominator for it to work reliably.

 

[bamacre]

Originally posted by: trOver
so do you think the new evga board would knock down the speed on 4x512?

I have only heard of that happening with AMD systems, not Intel. I'm running 4x512MB just fine, but with a Pent D system, not C2D.

 

[poohbear]

Originally posted by: bamacre
Dual channel only needs your memory installed in pairs. You can even run 2X1GB and 2X512MB (total 3GB) in dual channel.

that's for AMD too? u sure? thought they had to be the same size in pairs?

 

[imported_neloX]

Originally posted by: bamacre
No, get the 4x512MB. That way, you are in dual channel mode with 1GB (2x512MB), then later as well with 2GB (4x512MB). Dual channel only needs your memory installed in pairs. You can even run 2X1GB and 2X512MB (total 3GB) in dual channel.

Any idea if that would work on a Gigabyte S3? I always thought dual channel only worked with 2 slots no matter if all 4 slots were the exact same memory. But your saying they dont need to be, just need to be matched in pairs. Can anyone confirm this.

 

[Yellowbeard]

Some MOBOs are pickier than others when mixing ICs or even revisions of the same IC. You may want to check with Gigabyte and have a look at the online manual for their specific memory requirements.

Also keep in mind that if you buy a single DIMM now, you may not be able to find that same EXACT IC and revision combination. In "some" cases this can cause instability or even not allow you to boot. There are no guarantees but, I'd go with Gigabytes recommendation.

 

[Fike]

Originally posted by: Yellowbeard
Some MOBOs are pickier than others when mixing ICs or even revisions of the same IC. You may want to check with Gigabyte and have a look at the online manual for their specific memory requirements.

Also keep in mind that if you buy a single DIMM now, you may not be able to find that same EXACT IC and revision combination. In "some" cases this can cause instability or even not allow you to boot. There are no guarantees but, I'd go with Gigabytes recommendation.

This is exactly my experience too. I have heard that AMD systems are more sensative, but I don't know.

 

[imported_neloX]

So in theory matched pairs will work in dual channel, even if they are two different matched pairs occupying 4 slots? For example a Corsair 2x1gb 800mhz in the right slots along side say a Patriot 2x1gb 1000mhz in the correct slots, will mean essentially 2 different matched pairs but both running in dual channel, even if the timings/voltages/clock speeds between the matched pairs is different? Have i got that right? I'm not planning on it right now but just wondering for upgrades in a few years time/general knowledge.

 

[Yellowbeard]

Originally posted by: neloX
So in theory matched pairs will work in dual channel, even if they are two different matched pairs occupying 4 slots? For example a Corsair 2x1gb 800mhz in the right slots along side say a Patriot 2x1gb 1000mhz in the correct slots, will mean essentially 2 different matched pairs but both running in dual channel, even if the timings/voltages/clock speeds between the matched pairs is different? Have i got that right? I'm not planning on it right now but just wondering for upgrades in a few years time/general knowledge.

Well, I would say in theory that no, it's not supposed to work based on what MOBO makers typically advise. In many cases it does but, it is so hit and miss that is certainly is not a good choice.

Essentially what you are doing in this case is, if you use SPD, then you have the bios trying to set timings for 2 different SPD (1 Corsair and 1 Patriot ) at the same time. In many cases, you cannot boot due to this.

So, another option is to manually set timings that both modules can run which in this case would be somewhat of a compromise. The system can only run as fast as the slowest or weakest of the 4 modules will allow. So, more variables to try to overcome.

And, in general, 4 modules will not allow as much of an OC as 2. So if OCing is a priority, then go with 2 DIMMs when possible.

As to AMD being more sensitive to this, it may well be as the onboard memory controller is more sensitive to latencies, and thus latency differences. There's much more to it than all of this but, in general it is a bad idea to try to mix modules if you can avoid it.

 

[imported_neloX]

Yellowbeard, thanks for clearing that up for me.