Is there any practical issue with non-dual channel?

[phexac]

I am going to install Vista 64, so I ordered a 2x2GB RAM set from Corsair that I want to put into the system to replace the 2x1GB that I have right now.

My question is whether it's a good idea to try and add my 2x1GB to the configuration in order to get 6GB RAM total. As I understand it, what will happen is 4GB will run in dual channel configuration, and 2GB will run in single channel. My question is in what areas, if any, will my performance be negatively impacted? Is this a worthwhile thing to do?

Also since 4GB will be operating in dual channel mode, does that mean that for most applications, such as games, they will run on the dual-channel portion of memory and thus get the benefit of dual channel? Or am I getting this conceptually wrong?

Can someone give me a quick rundown of what happens or a link? Basically is adding 2 extra GB of RAM worth losing dual-channel performance? Thanks.

 

[Zapper48]

AFAIK populating all four memory slots should still be dual channel.

 

[error8]

Yes, you'll have 6 gigs in DUAL channel.

 

[phexac]

Originally posted by: error8
Yes, you'll have 6 gigs in DUAL channel.

Even if 2 of the modules are 2GB each, and the other 2 are 1GB each?

 

[DSF]

Originally posted by: phexac

Originally posted by: error8
Yes, you'll have 6 gigs in DUAL channel.

Even if 2 of the modules are 2GB each, and the other 2 are 1GB each?

If you have them distributed across the channels properly, you'll have 6GB of dual-channel RAM. Check your motherboard manual to make sure which DIMMs should go in which slots.

 

[n7]

Put the 2x2 GB in slots 1 & 3, & the 2x1 GB in slots 2 & 4.

You'll have 6 GB in dual channel.

In Vista, the more RAM, the merrier

 

[phexac]

Cool thanks, didn't know you could mix memory module size like that.

 

[n7]

It's nothing new

Many OEM systems (Dell, HP, etc.) come with 2x1 GB + 2x512 MB.

In fact that's how most 3 GB pre-builts are set up to maintain synchronous dual channel, though some are 3x1 GB (asynchronous dual channel).

Though actually, IIRC, it's technically now [on all semi-new Intel chipset] Flex Mode if there's 3 dimms, which is IIRC a bit different than asynchronous dual channel, but blah...i'm not going thru Intel whitepapers to confirm that.