Memory placement

[loglord]

Hello, my current rig is:

MSI K8N Diamond Plus s.939
AMD Athlon64 3800+ X2
2x512MB +2x1GB RAM memory (all DDR400/downclocked to DDR333 due to controller limitation)

I'd like to know if there's any difference when it comes to memory placement, currently I'm having both 512MB modules on slots 1 and 2, and the 2GB modules on slots 3 and 4. Would there be any performance difference if bigger modules were put in slots 1 and 2 instead? Dual channel is preserved, both sets of modules have equal units.

thanks in advance

 

[Harvey]

MSI's specs for your motherboard say that it supports DDR400. However, you forgot the basic rule... When all else fails, RTFM (Read The Freaking Manual).

If you lost yours, you can download it, here. The complete info you need is on pp. 2-6 - 2-7.

Cliffs:

Your motherboard supports dual channel RAM. Note the green and purple RAM sockets. For dual channel operation, you must put one 1 GB DIMM and one 512 MB DIMM in Channel A and one of each in Channel B.

The manual notes further constraints on the kinds of memory that will work when all four slots are used:

MSI Reminds You...

- Dual-channel DDR works ONLY in the 3 combinations listed in the table shown in the previous page.

- Please select the identical memory modules to install on the dual channel, and DO NOT install three memory modules on three DIMMs, or it may cause some failure.

- Always insert the memory modules into the GREEN slots first, and it is strongly recommended not to insert the memory modules into the PURPLE slots while the GREEN slots are left empty.

- Due to the South Bridge resource deployment, the system density will only be detected up to 3+GB (not full 4GB) when each DIMM is installed with an 1GB memory module.

For full info, check the relevant pages in the manual. It may be that your RAM will only work at 333 MHz. For more info, you can also check MSI's list of compatible RAM for your motherboard.

You may also want to check to see if later version of the BIOS would help. If you decide to update your BIOS, MSI's update process is a little different from other boards. Before you try it, READ THE INSTRUCTIONS CAREFULLY!

Good luck.

 

[loglord]

@Harvey thanks for the info, but I already have my manual, I know that the motherboard supports DDR400, however when all memory slots are filled with double sided modules the controller downclocks the frequency to 333Mhz...maybe I didn't ask my question properly so I'll try it again:

I got 2 sets of memory modules, 2x512 MB A-DATA and 2x1GB Kingston for a total 3GB of system RAM.. right now I have the 512MB modules in slot 1 and 2, and 1GB modules on slot 3 and 4. it is set up properly for dual channel work according to motherboard specs and manual. what I wanted to know is if there would be any difference in performance if I've put the 1GB modules on slot 1 and 2 so the 512MB modules would go on slot 3 and 4..the manual doesn't have any information about this 'issue', would the performance of the computer be better if I put the bigger modules on slots 1-2 or it doesnt make any difference...cos i've read some opinions that it is recommended putting the bigger modules in front, I'm just looking for an opinion on this from someone who knows more about these things

thanks again, much appreciated

 

[Harvey]

@Harvey thanks for the info, but I already have my manual...

Good. I just gave you the link in case you had lost it because the it has far more detailed info than I posted. However, I DID answer your question directly in my previous post. I said:

Your motherboard supports dual channel RAM. Note the green and purple RAM sockets. For dual channel operation, you must put one 1 GB DIMM and one 512 MB DIMM in Channel A and one of each in Channel B.

The manual also contains a diagram showing how various combinations of RAM should be installed.

If you're lucky, it may even work at 400 MHz once you install the modules correctly, but no guarantee because, as you noted, some motherboards can't support four DIMM's @ 400 MHz.