Difference between DDR3 SDRAM and Dual Channel

[xenonn]

There are so many different types of RAM, and I'm getting confused with their actual difference in terms of performance. What's the performance difference between a system with 8GB DDR3 SDRAM 1600MHz and one with 8GB Dual Channel 1600 MHz DDR3?

Are the differences between the 2 types of RAM negligible? How do I know which one I should choose? The cost between the 2 types of RAM has quite a gap.

 

[CaedenV]

DDR3 is the speed of the ram.
Duel channel is the way your ram is set up.


So if you are buying a modern system then you will be buying DDR3 ram, because everything runs on that right now (until DDR4 comes out in ~1 year with the release of Broadwell). But then you choose the speed of the ram (1333, 1600, or 1866), the timings (CL 6 through 12... but this typically does not matter on performance), and the configuration (single, duel, or quad).

All mainstream motherboards are duel channel capable. This means that you can populate 2 ram slots (dimms) on the motherboard and then the computer will stripe information across both sticks so that it can read and write to them independently. In theory this would net you a 2x performance boost... but in reality it is closer to a 20-30% speed increase over using a single channel.

High end boards (Sandy Bridge E or Ivy Bridge E systems) use a quad channel memory setup so that the system can read and write to 4 sticks of ram at the same time. Again, you would expect a major performance boost from this, but the sad reality is that it is only a ~10% gain over duel channel.

Considering modern prices I would suggest that you get 2 sticks of ram sold as a duel channel kit. Also, prices being what they are, you can typically get 1866 memory for the same price as 1600. You may never OC your system to take advantage of the 1866 speed, but these are typically better quality sticks that are less prone to failure, and they are normally $1-5 more which makes it a good choice.

When installing your memory be sure to pay attention! Most systems out there have pairs set up as dimm 1&3 and 2&4. Installing memory in dimms 1&2 on these systems will behave like a single channel setup, which is a 20% loss in potential speed that you are missing out on. HOWEVER, some motherboards (specifically some ASUS boards) have pairings on dimms 1&2 and 3&4. On these systems if you were to install the ram like normal in dimms 1&3 would be running in single channel.
If in doubt then look at matching colors as a duel channel pair, or refer to your motherboard manual.

 

[CaedenV]

Are you upgrading an existing system? Or building new?

Keep in mind that Intel is releasing new i5 and i7 processors at the end of the month. These new chips require new motherboards (and potentially power supplies), so I would highly suggest waiting a little bit if you are building a system with these parts. Celeron, Pentium, and i3 processors will not move to the new revisions (Haswell) until the fall, so if you are building one of these systems then don't worry about waiting.

 

[xenonn]

Does this mean that if I have 2 strips of single channel ram, then it doesn't really matter where I place them on the slots?

Also, Can I mix a 2 strips of dual channel ram with another 2 strips of single channel ram? Would it cause any performance issue?

 

[Cons29]

it does matter where you place them, usually (not sure if there are other cases, i think not) you place them using the first and third slot (1 and 3) and then 2nd and 4th if you have 4 sticks of ram. these are color coded most of the time if not all the time.

 

[xenonn]

I think I'm a little confused. Is the Dual Channel thing an attribute belonging to the mainboard? That is, all DDR3 SDRAM RAMs are the same.

Whether it has Dual Channel support or not, is not for the RAM to decide, but the mainboard's slot support?

 

[CaedenV]

Does this mean that if I have 2 strips of single channel ram, then it doesn't really matter where I place them on the slots?

Also, Can I mix a 2 strips of dual channel ram with another 2 strips of single channel ram? Would it cause any performance issue?

All ram is single channel. period. end of story.

You can purchase a "Duel channel kit" which simply has 2 sticks of single channel ram in it, and usually comes with a silly guarantee that they will work together in duel channel mode (which was a real problem 10+ years ago, but not so much anymore). You can also purchase 2 "single channel kits" and get the same effect of having 2 sticks of ram.

The goal of a duel channel kit is to ensure that you purchase ram with the same speed, quality, and timings. Buying sticks of ram from separate kits can cause issues where these things do not match, which then causes all of the ram in the system to run at the speed and settings of the lowest performing stick of memory. While this is still a bit of a problem for high performance memory that is going to be overclocked to the moon, it is not typically an issue anymore for normal overclocks, and really not an issues for all of those people (myself included) that run memory at stock settings.

 

[KRC]

After looking at about 5 different sites for an answer that actually had useful info but that I could understand I came across yours. I just wanted to say thanks!

DDR3 is the speed of the ram.
Duel channel is the way your ram is set up.


So if you are buying a modern system then you will be buying DDR3 ram, because everything runs on that right now (until DDR4 comes out in ~1 year with the release of Broadwell). But then you choose the speed of the ram (1333, 1600, or 1866), the timings (CL 6 through 12... but this typically does not matter on performance), and the configuration (single, duel, or quad).

All mainstream motherboards are duel channel capable. This means that you can populate 2 ram slots (dimms) on the motherboard and then the computer will stripe information across both sticks so that it can read and write to them independently. In theory this would net you a 2x performance boost... but in reality it is closer to a 20-30% speed increase over using a single channel.

High end boards (Sandy Bridge E or Ivy Bridge E systems) use a quad channel memory setup so that the system can read and write to 4 sticks of ram at the same time. Again, you would expect a major performance boost from this, but the sad reality is that it is only a ~10% gain over duel channel.

Considering modern prices I would suggest that you get 2 sticks of ram sold as a duel channel kit. Also, prices being what they are, you can typically get 1866 memory for the same price as 1600. You may never OC your system to take advantage of the 1866 speed, but these are typically better quality sticks that are less prone to failure, and they are normally $1-5 more which makes it a good choice.

When installing your memory be sure to pay attention! Most systems out there have pairs set up as dimm 1&3 and 2&4. Installing memory in dimms 1&2 on these systems will behave like a single channel setup, which is a 20% loss in potential speed that you are missing out on. HOWEVER, some motherboards (specifically some ASUS boards) have pairings on dimms 1&2 and 3&4. On these systems if you were to install the ram like normal in dimms 1&3 would be running in single channel.
If in doubt then look at matching colors as a duel channel pair, or refer to your motherboard manual.

 

[CaedenV]

no problem, glad I could help!