Dual Channel with 2 RAM modules with different capacity.

[alaintroll]

Hi there! I have an Core i3 3220, and ASRock H61M-GVS board and a Kingston Hyper-X 1600 2GB RAM. I´m considering a RAM upgrade, but in my country (Cuba) there is no big possibilities for doing it, so i found a Kingston Hyper-X 1600 but it has 4 GB of RAM. I have read that this CPU has something called Intel Flex Memory Access that allows the Dual Channel mode to work with modules with different capacities. Does anybody of you tried this before? You think is good as they claim? And if it works, would i have any problem with Memory Controller of the CPU?
I have also read, that with different sizes the RAM will work in Dual Channel but in asymmetric mode. This means a real lack of performance? What you recommend, buy this 4GB Hyper-X and add it to my 2GB Hyper-X, or wait for a twin of my current RAM. Thanks

 

[tweakboy]

Dude just grab a 16GB kit and never worry that you'll run out...

 

[nenforcer]

I have not heard of this Intel Flex Memory Access before but I believe it only applies to DIMM in seperate channels of the Dual Channel architecture.

Since your motherboard has 4 DIMM slots each channel is composed of 2 slots, Channel A and Channel B.

You have to have identical sizes in the 2 slots that match a channel, but each channel can have differing capacities.

Since you only are dealing with 2 memory DIMM's I would wait for a twin of your current RAM.

 

[Blastman]

The difference between single channel and dual channel memory performance in the vast majority of applications averages 1-2% at most. THG ran a suite of benches comparing triple/dual/single channel memory performance on a i7-920. Single channel averaged 1.5% slower than dual channel, and dual channel 0.6% slower than triple channel. You won't notice the difference in performance between running in single or dual channel mode in the vast majority of tasks so you might as well get the 4GB stick if you need more memory and that's what's readily available.

There are also some tests on the flex mode performance and it was better than single channel performance. So the difference should be less than 1% when running 4+2 GB flex mode rather than a 2+2Gb or 4+4GB dual channel setup.

You should note that the above applies to CPU oriented tasks. Since the i3-3220 iGPU also uses the main system DDR3, its performance will also be affected by running single channel vs dual channel mode.

Maximumpc ran a laptop (HD Graphics 3000 core in the 2.7GHz Core i7-2620M) and they saw as much as 20% better performance in gaming on the iGPU on dual channel memory versus single channel mode. They didn't test flex mode which should be better than the single channel mode, but if you game on the iGPU you may see maybe 5% or so ??? … drop in performance in flex mode, but I don't think it would be really much to worry about.

 

[alaintroll]

Thanks! It was very clarifying.

 

[tweakboy]

Spend 35 dollars and buy a cheap 8GB kit. Its lifetime warranty..

buy a kingston or mushkin . thx...