4GB Dual Channel or 8GB Single Channel

[Mr. Gruntsworthy]

My motherboard, an Asus P5Q SE LGA775 ATX PCI-E EPU MB, has four DDR2 memory slots, with Dual-Channel architecture. Please correct me if i'm wrong, but does that mean that I can use them for four sticks @ single channel, or 2 x 2 sticks dual channel? or is it only dual channel? That part confuses me.

Anyways, I was planning on getting two OCZ 2P8004GK 2x2G PC2-6400 Platinum Kits. Do I need dual-channel capable RAM, or does any RAM run in dual-channel if I have two of the exact same type in each slot? With the two kits, I'll have four sticks of 2GB (all of the same type); so I was wondering if that RAM is capable of being used Dual-Channel. If so, i'd rather go 4GB dual-channel, but if not, I guess I'll have to go 8GB single-channel (I know there's no point to it as nothing uses that much, but it would still be fun to have).

Information much appreciated :)

[Eldonko]

Two sticks is dual channel, a 2x2GB kit is what you want.

[Mr. Gruntsworthy]

Originally Posted by Eldonko

Two sticks is dual channel, a 2x2GB kit is what you want.

so, If i get two 2x2GB kits, that means I can run 4GB in dual channel mode?

eh, i wonder how much of an increase in performance i'll get

[Eldonko]

It depends on your specific board but in general today's boards support dual channel using all four memory slots. There is not much point in buying more 4GB of RAM though unless you like spending money unnecessarily. You also need a 64bit OS to access more than 3GB..

[paphman910]

Originally Posted by Mr. Gruntsworthy

so, If i get two 2x2GB kits, that means I can run 4GB in dual channel mode?

eh, i wonder how much of an increase in performance i'll get

The P5Q supports up to 16 Gigs of RAM. If you get two 2x2GB kits that means each pair of RAM will run on its own channel and it will run 8GB in dual channel mode.

I don't think you will get much performance difference in dual channel mode. I am not sure about how much improvement.

Paphman910

[Mr. Gruntsworthy]

my new rig will have vista 64-bit, so don't worry about that.

so you're telling me I indeed can have 4GB dual-channel? (two pairs of two sticks)

[Eldonko]

Yes, stick to 2 or 4 sticks and you will have dual channel.

[Mr. Gruntsworthy]

awesome :)

just out of curiosity, what does dual-channel offer in benefits anyways? simultaneous acess or something? Ive always wondered.

[Eldonko]

Basically it doubles the amount of available memory bandwidth by adding a second parallel channel. This second channel reduces the bottleneck of mem keeping up with processor speed. For performance, dual channel gives about a 5% gain in mem intensive tasks.

[MushkinGreg]

Also, regarding dual channel.
I noticed huge drop in gaming performance using single channel mode, even though memory benchmarks shows little change in performance.