2x2gb dual channel or 3x2gb running in single channel?

[iafatel]

I'm grabbing my ram on my current desktop 3x2gb in my i7 920 and tossing it in a build for my parents, an i3 2100.

I'm reading that the Sandy bridge currently doesn't have triple channel support. Does the extra 2gb make up the difference for the loss of running in dual channel?

 

[jaquith]

You will lose the Dual Channel but the performance differences are negligible and the benefits of additional RAM outweigh the Dual Channel lose.

edit: also many i7 920 era RAM kits were 1.65v - there's no proven studies but Intel recommends the use of 1.50v RAM. The additional voltage does add stress to the Sandy Bridge's IMC. RAM is pretty cheap in 2x4GB kits ~$60 and IMO might be a good long-term choice.

 

[iafatel]

errrm, 1 for 6gb single channel and 1 for 4gb dual channel. Not sure what to do now!

 

[jaquith]

Okay, what are you doing with your i7 920 build?

IF you want to give your parents your left overs then sure give them the 3x2GB kit and replace yours with a 3x4GB kit. Just keep in mind that you're probably putting a 1.65v kit in a 1.50v preferred Sandy Bridge; note my repeated comments. IF the RAM is only running DDR3 1333 MHz 'SPD' then 9/10 it's 1.50v and will run just not in Dual Channel. Sandy Bridge Dual vs Non-Dual is very negligible and unless your folks are the 'Borg' they'll never notice.

If you're dumping an i7 920 for i3 2100 Sandy Bridge then you're wasting a very good system; the differences are small in 'Real World' ; see -> http://www.anandtech.com/show/4083/the-sandy-bridge-review-intel-core-i7-2600k-i5-2500k-core-i3-2100-tested/15

CPU Mark -> http://www.cpubenchmark.net/high_end_cpus.html
Intel Core i3-2100T @ 2.50GHZ -> 3,259 ; no way to OC
Intel Core i7 920 @ 2.67GHz -> 5,564 ; can easily OC

 

[jaquith]

Note the edit above, you 'can' bastardize the Sandy Bridge RAM anyway you want as long as it has the same Frequency, CAS, Voltage & Type.

Examples that work:
Dual Channel
2x__GB
2x2GB + 2x4GB

Non Dual Channel
1x__GB, or 3x__GB

edit:
32-bit ; 2x2GB {3.0~3.5GB usable}
64-bit ; 3x2GB {6GB usable less iGPU/HW Reserved}

 

[iafatel]

Best answer selected by iafatel.