A8N-SLI: 2 DIMMS or 4 DIMMS?

[dfurgiuele]

Hi there,

Last month I built a new PC, 4400 Athlon X2 with 1GB of DDR 400 RAM. Everything was working great. Last week, I decided that I would purchase additional RAM for it; so I went back to my online vendor, and ordered the same part number of the memory that I already had. The memory arrived I got it all installed...

The system, at POST, states that I have 2GB of memory (no surprises there), however it also says that the memory is detected (by SPD) as 333Mhz. When I had just two sticks, it detected at 400Mhz. I thought I had read somewhere that when you were running 4 sticks of memory, the system "underclocks" (for lack of a better word) the memory for compatibilty reasons; is there any truth to that?

I was able to go into BIOS and set the memory (manually) to 400Mhz, and everything appears fine. Is this a bad thing to do, given the SPD configuration returning that value for the RAM? If it does "underclock" can anyone explain why this is so?

Thanks,
Drew

 

[Ots]

The nForce4 chipset defaults to 333 MHz with four sticks. It's a peculiarity with the chipset. If you can set it to 400 MHz and it's stable, cool. I've read that others have had to alter other settings in order to be stable at 400 MHz. I've never done it but maybe someone else can comment on that.

 

[a1ien]

It has to do with AMD's memory controller being on the cpu itself. You might want to run some stress tests to see if it's stable, such as Prime95 for a few hrs. But in my opinion, the better solution would be dual channel 2GB (2 x 1GB).

 

[Covered_in_bees]

The nForce4 chipset defaults to 333 MHz with four sticks. It's a peculiarity with the chipset. If you can set it to 400 MHz and it's stable, cool. I've read that others have had to alter other settings in order to be stable at 400 MHz. I've never done it but maybe someone else can comment on that.

A lot of motherboard manufacturers are doing this 'for stability reasons' (at least that's the excuse ASUS game me). Most motherboards will allow you to manually set the memory clock speed to 400MHz (well, 200MHz in BIOS, which is then doubled). However, I've noticed some ASUS motherboards still don't support this well (they have an AUTO and LIMIT option, but when LIMIT is set to 200MHz, it remains at 166MHz, as it's still under the limit).

If you have managed to manually set it back to 200MHz, and the system is stable, then that's fine. It's what the motherboard manufacturers recommend.

 

[mpjesse]

I have the same board w/ 4 DIMMs. What you did is just fine (I had to do it too). There's also a BIOS update to fix that little issue. I think it's v1009 on Asus's site. But if forcing it to run at 400mhz is working fine, I wouldn't bother.

-mpjesse

 

[bazza]

if you buy this MB, chances are you're gonna OC anyway so you have to set the mem freq anyway

an older bios had a few probs with 4 sticks of ram @ 400MHz but new one seems fine

 

[ggillespie]

Are there any software program that fixes this problem. I don't feel confident or knowledgeable enough to go and change my bios and motherboard settings.
I've tried MemTurbo4, but still getting memory errors when my computer gets overloaded.

I appreciate any advice

Greg