Is there a difference in performance between having 4x1 GB RAM modules and 2x2 GB RAM modules?
Also, is the answer different depending on if it's DDR2 or DDR3?
Posted Dec 5, 2009, 12:28 AM UTC
3431
The first uses more RAM slots.
17
No human would ever be able to tell.
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Unless your system crashes with 4 modules under overclocking. I've had to go down to a single stick on occasion.
1
Some motherboards will drop the speed of the RAM modules when you drop in all four.
9
This has less to do with the amount of modules as it has to do with the amount of ranks. Dual-sided module with 16 chips = 2 ranks.
If you have four single-rank modules, it is essentially the same as two dual-rank modules. The speed drop you saw was solely due to having 4 dual rank modules, which is more stressful to the memory controller.
3
My old p35-ds3l had numerous problems with clocking the ram with 4x1gb voltages and timings. Memtest'd with pairs and was fine just had to manually clock with 4. Very odd.
1
Did you try upping the MCH voltage?
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Was up to about +.4/+.5 V (just about max on the board) and finally gave up since was still not stable. Even tried lowering the speed of the ram. I have a feeling was related to the board and not the ram.
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Theoretically, yes. Will you see it opening Firefox and going to a porn site? No.
9
Hmm, assuming he has a dual channel-capable motherboard (which I suppose every single one is these days, except those with more than dual), where does the difference come in? Assuming, as stated by luksy, that "the modules run at the same speed and there are no funny motherboard tricks" (such as them being set to another command rate which IIRC happened with nForce4).
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so true, web surfing and porn is all we use it for anyway.
EDIT: OK occasionally gaming.
0
yes, i would go with 2x2gb modules because:
a: leaves you 2 slots for upgrading later to 6 or 8gb
b:4x1gb modules puts more strain on the NB, so you overclocking ability on the ram and the proc would go down
oh and ddr3 has higher bandwidth(good) and higher latency(bad) -makes the higher bandwidth ddr2 faster than low bandwidth ddr3. high bandwidth ddr3 is fastest atm though.
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oh and ddr3 has higher latency(bad)
No it doesnt. DDR3 1600 with CAS 8 has the exact same latency as DDR2 800 with CAS 4.
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http://forums.macrumors.com/archive/index.php/t-654277.html
you have to have double the bandwidth to get the same performance
1
Ok, if I understand it correctly, it goes like this:
DDR2 or 3 will get you dual channel when running two sticks. DDR3 can get you triple channel with 4 sticks if you put them in a 2-1-1 configuration. Meaning that of the six slots, you fill the first two, put one stick in the second pair of slots and one stick in the third pair of slots. If you go with 2-2 in the banks, then it should fall back to dual channel.
There is a performance increase between dual and triple channel, but the increase is apparently negligible compared to the increase you get from the first dual channel boost.
The answer is a little different between DDR2 and DDR3 as DDR2 isn't capable of triple channel.
I usually opt for less sticks with higher values because it makes upgrading easier down the road. Ram sticks are plentiful. Ram slots are not.
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Note that the only way you'll get triple channel memory is with an X58 motherboard. No other chipsets really support it yet, and that includes LGA 1156 and AM3.
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On top of that, you cant have triple channel with 4 sticks. 3 or 6 sticks only.
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Well, I've seen some cheaper LGA 1366 boards that have 4 slots. They're kinda weird though - the first 3 slots are triple channel, and the last slot is just single channel. One of my friends got a board like that, and I'm honestly not sure what Intel was thinking when they designed it.
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In that case, you are going to get triple channel with 3 sticks only. It is an odd design, indeed.
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Triple channel Barely adds 1 or 2 % RL performance anyways.
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there can in theory be a difference depending mainly on your memory controller and dimm. interleaved memory (across multi-channels in your case, 2x2) can hide latency - especially DDR3 where the burst length is larger.
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Strangely, my gigabyte motherboard would boot with 2x 1gb, 2x 2gb, 4x 2gb (what i have now) but refused to boot with 4x 1gb, I still don't know why.....
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No
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best answer.
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Assuming the modules run at the same speed and there are no funny motherboard tricks, if there is a difference, you won't notice it.
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Edit: sorry see other posts.
I don't have any technical information to point to, but I do believe the communication path for the 1 module is the same as the 2 modules. Data being split between the two modules is not likely to cause performance issues. And obviously if they aren't of the same type of RAM the performance will change.
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Yes. 2 slots.
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For many small operations 4x1, for massivly hard operations 2x2.
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Not enough information, depends on the memory controller and the number of chips on the modules. The full speed is only achieved under certain conditions. Read the memory recommendations in your motherboard manual.
Relevant to your question, no difference otherwise between DDR2 and DDR3, except DDR3 is faster memory going forward. I've read that DDR3 hasn't yet achieved it's full potential in many cases.
What infiniband forgot to tell, is that you need to look if the motherboard supports Dual or Triple channel DDR2/DDR3. It basically combines the bandwidth of 2 or 3 memory banks. In practice this gains you a few percent in performance.
I didn't forget, I tried to phrase it in a way layman could understand without throwing a term like "dual-channel" at them. That's why I said to look in the motherboard manual. I didn't think the person would understand the concept of multi-channel memory just from my message; I thought the manual would do a better job of it. Saying that only certain dimms are certified by the motherboard manual for multi-channel use only going to confuse them.