Dual channel DDR3 1333 vs single channel DDR3 1600 RAM?

Question

I'm building a FreeNAS file server and have been searching for ram. What's available is either:

2x 8 GB DDR3 1600 single channel (CL11)

or

2x 8 GB DDR3 1333 dual channel (CL9)

Price difference doesn't matter. I just want to know which would be better.

Solution

Dual Channel RAM

Depending on the application, Dual Channel ram can be anywhere from 1% to 10% faster than single channel.

http://www.tomshardware.com/reviews/PARALLEL-PROCESSING,1705-15.html
http://www.hardwaresecrets.com/article/133

RAM Speed

Ram speeds are determined by your northbridge chipset. The speed on the ram only indicates what it is 'rated' for.

Putting DDR 1600 in a computer that maxes out at 1333 will give you 0 benefit. The advantage to faster ram comes if you are over clocking your bus.

That said, you should always buy RAM that is rated for at least what the northbridge will support. My Mac book pro clocked down from 1600 to 1333 when I upgraded one of my RAM sticks.

Other thoughts

The differences in RAM is so slight, that you will see much bigger return on investment if you splurge and get an SSD.

http://www.mmo-champion.com/threads/1200108-Basic-Ram-Question-DDR3-1333-vs-DDR3-1600
http://www.pcauthority.com.au/Feature/128551,does-faster-ram-really-make-a-difference.aspx

Comments

[spuder]

Many anecdotal reports have suggested that dual channel offers a 10% increase over single channel, where as ddr 1600 is only 1% faster than 1333. Check the maximum pc and tomshardware forums for benchmarks of people who have tried this.

[gavsiu]

I just realized I worded my question wrong, but seems like you got my point. I meant both are 2x 8gb sticks.

[spuder]

glad to hear, I'm going to look up some supporting resources, and turn this into an answer.

[ganesh]

If your motherboard support dual channel memory access then you can use both "8 GB DDR3 1600 single channel (CL11)" DIMMs for dual channel access. There is no difference between dual channel DIMMs and identical single channel DIMMs. The dual channel sets just mean "We made sure these two have identical specs so you can use them in a dual channel configuration".

[ganesh]

Also, more memory allows for more disk caching. This means that if you access the same data multiple times (e.g. when you open a folder with MP3 and replay the same song a bit later - Song A, Song B, reclick on song A which will be loaded from the cache-) then more RAM is better than faster RAM. Other than that latency and single/dual/tripple/.. channel memory etc is not likely to be your limiting factor. This is most likely the NICs, the drive or the CPU, neither of which specs are in the OP.

[gavsiu]

The motherboard and cpu supports 1600/1333. I won't be spending on SSDs. I'm getting Western Digital Red drives.

[ganesh]

Concerning "RAM speeds are determined by your northbridge chipset"; memory access speed is determined by the memory controller, which used to be in the northbridge**. On any modern CPU it is in the CPU.