4 GB possible on any C2D / Conroe compatible chipset?

[Falc410]

Hi,

 

I've wanted to purchase a new computer with a Core 2 Duo compatible chipset, so I had my eyes on a Asus P5B Deluxe board with Intel 965 Chipset (I don't want to discuss pro or cons of this particular board).

 

Now Asus is advertising these boards to be compatible with up to 8 GB DDR2-800 RAM.

 

But my local hardware dealer warned me that this setup might not be possible as the current 1 GB Modules are double-sided and the chipset limitation is 6 banks, so that you can install max. 3 modules (as 3x2=6).

 

So he tested the mainboard with a different memory (MDT) and it didn't work with 4 GB.

 

Asus website says for the P5B Deluxe in the QVL specifications for the Corsair CM2X1024-6400C4 (the memory I wanted to purchase 4 times): C*

 

C*: supports 3 modules inserted into both the yellow and black slots as pairs of Dual-Channel memory configuration

 

So are we talking about 3 modules now? So maximum 3 GB of RAM, or are we talking of two pairs which would equal 4 modules and 4 GB RAM. (see attachment). Maybe it's a print error?

 

The only mainboard I found which can handle 4 slots with double-sided RAM is the old nforce4 for Intel from Asus which does not support Conroe CPU's.

 

So what do you think? Is it possible to have a Core 2 Duo CPU and 4 GB of RAM or not? (also please I don't want to discuss if it's a good idea or not to have 4 GB of RAM - lets just stick to the point, thanks)

[RJLeong65]

Actually, memory modules need to be installed in pairs for dual-channel memory controller operation. But using only three modules will force single-channel memory controller operation on any Intel platform. And if the Intel memory controller is limited to 6 banks of memory total, this means that you can use only 2 double-sided modules plus 2 single-sided modules if you want to keep it dual-channel. Unfortunately, this will currently limit your maximum memory capacity to 3GB, because all current 1GB and larger DDR2 modules on the market (as well as some 512MB DDR2 modules) are double-sided.

 

The above statement assumes that you'll be using DDR2-800/PC2-6400 memory. What many people forget to tell you is that you can use 4 double-sided DDR2 modules on an Intel chipset mobo, but then you will have to use DDR2-667/PC2-5300 or DDR2-533/PC2-4200 modules in order for such a memory setup to work (at this point, many DDR2-800/PC2-6400 modules have trouble working reliably at slower-than-rated speeds).

[Falc410]

Thanks for the reply.

 

So the gist of it is: I can have 4 double-sided modules installed but then the memory speed drops to DDR2-667.

 

Did I get it correct ?

 

So the Intel 965 Chipset (on Asus P5B for example) can handle more then 6 banks?

[RJLeong65]

Thanks for the reply.

 

So the gist of it is: I can have 4 double-sided modules installed but then the memory speed drops to DDR2-667.

 

Did I get it correct ?

 

So the Intel 965 Chipset (on Asus P5B for example) can handle more then 6 banks?

 

Actually, most C2D-compatible motherboards are extremely picky as to which DDR2-800 modules to use (i.e., they may not work with all DDR2-800 modules). You will have to use modules that are rated for DDR2-667 or DDR2-533 speed if you want to use 4 double-sided sticks. (Four DDR2-800 modules underclocked to DDR2-667 or DDR2-533 will not work.)

[Falc410]

I see. Thanks for the reply.

 

I will wait for some information about the Nforce 690i chipset then. Maybe this one can handle 4 DS modules better.

[RAM GUY]

Its not the Chipset its the memory controller in the CPU and all un-buffered platformas will have the same limitations. AMD and Intel Both!